Sample records for sar interferometry differential

This paper reports on the potential of differentialSARinterferometry to map land subsidence. After a presentation of the methodology, the focus will be on feasibility demonstration and accuracy assessment. The theoretical considerations are verified with the selected cases Ruhrgebiet, Mexico City, Bologna, and Euganean Geothermal Basin, representing fast (m/year) to slow (mm/year) deformation velocities. The accuracy of the generated deformation maps and the maturity of the required process...

This paper reports on the potential of differentialSARinterferometry to map land subsidence. After a presentation of the methodology, the focus will be on feasibility demonstration and accuracy assessment. The theoretical considerations are verified with the selected cases Ruhrgebiet, Mexico City, Bologna, and Euganean Geothermal Basin, representing fast (m/year) to slow (mm/year) deformation velocities. The accuracy of the generated deformation maps and the maturity of the required process...

Ground deformation measurements have contributed to a better understanding of the processes and mechanisms involved in natural hazards. Those include landslides, subsidence, earthquakes and volcanic eruptions. Spaceborne Differential Interferometric Synthetic Aperture RADAR (DInSAR) is a well studied technique for measuring ground deformation. Quality of deformation measurements, however, is often degraded by decorrelation. With the advent of fully polarimetric SAR satellite sensors, polarimetric optimization techniques exploiting polarimetric diversity improve the phase quality of interferograms. In this paper, we analyzed three polarimetric optimization methods to determine the optimal one for application in an arid natural environment. We considered coherence decomposition in single and double phase center scenarios. Coherence estimation bias associated with each optimization method has been analyzed. We compared the derived displacement values with terrestrial GPS measurements. The study shows that polarimetric optimization increases the number of coherent pixels by upto 6.89% as compared with a single polarization channel. The study concludes that polarimetric optimization coupled with DInSAR analysis yields more reliable deformation results in a low coherence region.

In China, the surface deformation of ground has been a significant geotechnical problem as a result of cracks in the ground surface, collapsing of house, and subsidence of roads. A powerful technology for detecting surface deformation in the ground is differentialinterferometry using synthetic aperture radar (INSAR). The technology enables the analysis from different phase of micro-wave between two observed data by synthetic aperture radar (SAR) of surface deformation of ground such as ground subsidence, land slide, and slope failure. In January 2006, the advanced land observing satellite was launched by the Japan Aerospace Exploration Agency. This paper presented an analytical investigation to detect ground subsidence or change caused by mining, overuse of ground water, and disaster. Specifically, the paper discussed the INSAR monitoring technology of the mine slope, including INSAR data sources and processing software; the principle of synthetic aperture radar interferometry; principles of differentialSARinterferometry; and INSAR technology to slope monitoring of the Haizhou open pit mine. The paper also discussed the Haizhou strip mine side slope INSAR monitoring results and tests. It was concluded that the use of synthetic aperture radar interferometer technique was the optimal technique to provide three-dimensional spatial information and minimal change from ground surface by spatial remote sensing device. 18 refs., 5 figs.

Advanced DifferentialSARinterferometry (A-DInSAR) is a technique monitoring large-coverage surface deformations using a stack of interferograms generated from several complex SLC SAR images, acquired over the same target area at different times. In this work are described the results of a procedure to calculate terrain motion velocity on highly correlated pixels (E. Biescas, M. Crosetto, M. Agudo, O. Monserrat e B. Crippa: Two Radar Interferometric Approaches to Monitor Slow and Fast Land Deformation, 2007) in two area Gemona - Friuli, Northern Italy, Pollino - Calabria, Southern Italy, and, furthermore, are presented some consideration, based on successful examples of the present analysis. The choice of these pixels whose displacement velocity is calculated depends on the dispersion index value (DA) or using coherence values along the stack interferograms. A-DInSAR technique allows to obtain highly reliable velocity values of the vertical displacement. These values concern the movement of minimum surfaces of about 80m2 at the maximum resolution and the minimum velocity that can be recognized is of the order of mm/y. Because of the high versatility of the technology, because of the large dimensions of the area that can be analyzed (of about 10000Km2) and because of the high precision and reliability of the results obtained, we think it is possible to exploit radar interferometry to obtain some important information about the structural context of the studied area, otherwise very difficult to recognize. Therefore we propose radar interferometry as a valid investigation tool whose results must be considered as an important integration of the data collected in fieldworks.

The aim of this paper is to propose a methodology to perform inverse numerical modelling of slow landslides that combines the potentialities of both numerical approaches and well-known remote-sensing satellite techniques. In particular, through an optimization procedure based on a genetic algorithm, we minimize, with respect to a proper penalty function, the difference between the modelled displacement field and differential synthetic aperture radar interferometry (DInSAR) deformation time series. The proposed methodology allows us to automatically search for the physical parameters that characterize the landslide behaviour. To validate the presented approach, we focus our analysis on the slow Ivancich landslide (Assisi, central Italy). The kinematical evolution of the unstable slope is investigated via long-term DInSAR analysis, by exploiting about 20 years of ERS-1/2 and ENVISAT satellite acquisitions. The landslide is driven by the presence of a shear band, whose behaviour is simulated through a two-dimensional time-dependent finite element model, in two different physical scenarios, i.e. Newtonian viscous flow and a deviatoric creep model. Comparison between the model results and DInSAR measurements reveals that the deviatoric creep model is more suitable to describe the kinematical evolution of the landslide. This finding is also confirmed by comparing the model results with the available independent inclinometer measurements. Our analysis emphasizes that integration of different data, within inverse numerical models, allows deep investigation of the kinematical behaviour of slow active landslides and discrimination of the driving forces that govern their deformation processes.

This paper presents possibilities for monitoring man- made surface deformation on example of two areas (Fig. 1): Upper Silesian Coal Basin and Lubelskie Coal Basin (Poland). Synthetic Aperture Radar (SAR) images acquired by Sentinel-1A satellite are utilized in subsidence studies. Satellite radar interferometry technique (InSAR) was used to detecting and monitoring subsidence. There are clearly visible on obtained interferograms subsidence troughs as a distinctive concentric fringes. This study is a part of initiated the SSUMMO project (Surface Subsidence Multidisciplinary Monitoring). The project will provide multidisciplinary monitoring of mining areas and it will prepare the methodology and research software for continuous observation of the impact of exploitation on surface.

Full Text Available We present a new digital elevation model (DEM of the Austfonna ice cap in the Svalbard Archipelago, Norwegian Arctic. Previous DEMs derived from synthetic aperture radar (SAR and optical shape-from-shading have been tied to airborne radio echo-sounding surface profiles from 1983 which contain an elevation-dependent bias of up to several tens of metres compared with recent elevation data. The new and freely available DEM is constructed purely from spaceborne remote sensing data using differentialSARinterferometry (DInSAR in combination with ICESat laser altimetry. Interferograms were generated from pairs of SAR scenes from the one-day repeat tandem phase of the European Remote Sensing Satellites 1/2 (ERS-1/2 in 1996. ICESat elevations from winter 2006–08 were used as ground control points to refine the interferometric baseline. The resulting DEM is validated against the same ground control points and independent surface elevation profiles from Global Navigation Satellite Systems (GNSS and airborne laser altimetry, yielding root mean square (RMS errors of about 10 m in all cases. This quality is sufficient for most glaciological applications, and the new DEM will be a baseline data set for ongoing and future research at Austfonna. The technique of combining satellite DInSAR with high-resolution satellite altimetry for DEM generation might also be a good solution in other glacier regions with similar characteristics, especially when data from TanDEM-X and CryoSat-2 become available.

Short temporal baseline and multiple ground deformation information can be derived from the airborne differential synthetic aperture radar Interforemetry (D-InSAR). However, affected by the turbulence of the air, the aircraft would deviate from the designed flight path with high frequent vibrations and changes both in the flight trajectory and attitude. Restricted by the accuracy of the position and orientation system (POS), these high frequent deviations can not be accurately reported, which would pose great challenges in motion compensation and interferometric process. Thus, these challenges constrain its wider applications. The objective of this paper is to investigate the accurate estimation and compensation of the residual motion errors in the airborne SAR imagery and time-varying baseline errors between the diffirent data acquirations, furthermore, to explore the integration data processing theory for the airborne D-InSAR system, and thus help to accomplish the correct derivation of the ground deformation by using the airborne D-InSAR measurements.

National Aeronautics and Space Administration — Polarimetric radar interferometry (PolInSAR) is a new SAR imaging mode that is rapidly becoming an important technique for bare earth topographic mapping, tree...

On 10 January, 1998 an earthquake of Ms=6.2occurred in the Zhangbei-Shangyi region of North China.The surface seismic deformation was measured in the previous study using the 3 pass ERS-1/2 SARdifferential interferometric technology (D-INSAR). In this note the focal mechanism of Zhangbei-Shangyi earthquake is estimated from the D-INSAR measurement of surface deformation based on a standard elastic dislocation model for seismic displacement. The inversion procedure is an iterative, linear least-squares algorithm. Through the relation between the focal parameters and displacement in the line of sight direction measured in the radar interferogram, the optimum focal parameter set is derived. The results show that the seismic fault of Zhangbei-Shangyi earthquake is a thrust fault dipping SW with a large right-lateral displacement component.The strike and dip are 95° and 30° respectively on a fault patch of 12 km long by 14 km wide. Its hypocenter is located at N40°58', E114°21', and 7.5 km in depth. The estimated slip vector is 0.728 m with a rake of 105.95°, the trend of slip is NW13.26°, and M0is 2.69×1018 N @ m.

Full Text Available In the present work, the DifferentialSARInterferometry (DInSAR technique has been applied to study the surface movements affecting the sedimentary basin of Cassino municipality. Two datasets of SAR images, provided by ERS 1-2 and Envisat missions, have been acquired from 1992 to 2010. Such datasets have been processed independently each other and with different techniques nevertheless providing compatible results. DInSAR data show a subsidence rate mostly located in the northeast side of the city, with a subsidence rate decreasing from about 5–6 mm/yr in the period 1992–2000 to about 1–2 mm/yr between 2004 and 2010, highlighting a progressive reduction of the phenomenon. Based on interferometric results and geological/geotechnical observations, the explanation of the detected movements allows to confirm the anthropogenic (surface effect due to building construction and geological causes (thickness and characteristics of the compressible stratum.

InSAR (Interferometric Synthetic Aperture Radar) and D-InSAR (Differential InSAR) are rapidly developed new technologies of space geodesy during the late 20th century, and now obviously become hot research topics in the field of microwave remote sensing. Compared with the other sensors, InSAR possesses many incomparable advantages such as the capability to work at all-time and under all weather, very high spatial resolution and strong penetrability through the ground surface. This paper introduces general status of SAR, InSAR, D-InSAR technology, and the principles of InSAR and D-InSAR. New theories and the potential problems of (D-)InSAR technology are largely discussed, including multi-baseline interferometry, Pol-InSAR technique, the correction of atmospheric effects, permanent Scatterers method, the synthesization technique between InSAR and GPS, LIDAR etc., and the InSAR parallel algorithm. Then the new applications of InSAR and D-InSAR are described in detail including 3D topographic mapping, deformation monitoring (including surface subsidence, landside monitoring and ITRF's foundation and maintenance, etc.), thematic mapping (including agriculture and forestry, oceanic surveying and flood monitoring, etc.) and meteorology etc.. Finally, the prospect and future trends in InSAR development are summarized.

Full Text Available Due to their remoteness, altitude and harsh climatic conditions, little is known about the glaciological parameters of ice caps on the Tibetan Plateau. This study presents a geodetic mass balance estimate of the Purogangri Ice Cap, Tibet's largest ice field between 2000 and 2012. We utilized data from the actual TerraSAR-X mission and its add-on for digital elevation measurements and compared it with elevation data from the Shuttle Radar Topography Mission. The employed data sets are ideal for this approach as both data sets were acquired at X-band at nearly the same time of the year and are available at a fine grid spacing. In order to derive surface elevation changes we employed two different methods. The first method is based on differential synthetic radar interferometry while the second method uses common DEM differencing. Both approaches revealed a slightly negative mass budget of −44 ± 15 and −38 ± 23 mm w.eq. a−1 (millimeter water equivalent respectively. A slightly negative trend of −0.15 ± 0.01 km2 a−1 in glacier extent was found for the same time period employing a time series of Landsat data. Overall, our results show an almost balanced mass budget for the studied time period. Additionally, we detected one continuously advancing glacier tongue in the eastern part of the ice cap.

Developing and improving methods to monitor both natural and non-natural environments such as forest and urban in space and time is a timely challenge. To overcome this challenge, we created a software platform - TomoSAR. The kernel of this platform supports the entire processing from SAR, Interferometry, Polarimetry, to Tomography (so called TomoSAR). The objective of this paper is to introduce this platform about its design architecture and its capacity. We showed four examples to highlight the TomoSAR platform capacities. First, the useful of the interferometric coherence of TOPS Sentinel-1 for land cover classification was highlighted. Second, a TOPS Sentinel-1 differential interferogram in a complex scenario volcano was successfully produced. Third, a TOPS Persistent Scatterers Interferometry analysis for estimating subsidence in Ho Chi Minh City area was demonstrated. Finally, the capability of processing and modelling of 3D P-band tomography in volume forest scattering were reported.

Ground deformation in Mexicali Valley, Baja California, Mexico, the southern part of the Mexicali-Imperial valley, is influenced by active tectonics and human activity, mainly that of geothermal fluid extraction in the Cerro Prieto Geothermal Field. Significant ground deformation, mainly subsidence (~ 18 cm yr-1), and related ground fissures cause severe damage to local infrastructure. The technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) has been demonstrated to be a very effective remote sensing tool for accurately measuring the spatial and temporal evolution of ground displacements over broad areas. In present study ERS-1/2 SAR and ENVISAT ASAR images acquired between 1993 and 2010 were used to perform a historical analysis of aseismic ground deformation in Mexicali Valley, in an attempt to evaluate its spatio-temporal evolution and improve the understanding of its dynamic. For this purpose, the conventional 2-pass DInSAR was used to generate interferograms which were used in stacking procedure to produce maps of annual aseismic ground deformation rates for different periods. Differential interferograms that included strong co-seismic deformation signals were not included in the stacking and analysis. The changes in the ground deformation pattern and rate were identified. The main changes occur between 2000 and 2005 and include increasing deformation rate in the recharge zone and decreasing deformation rate in the western part of the CPGF production zone. We suggested that these changes are mainly caused by production development in the Cerro Prieto Geothermal Field.

This paper introduces a few simple scattering models intended for the application of polarimetric SARinterfer-ometry to land ice. The principal aim is to eliminate the penetration bias hampering ice sheet elevation maps generated with single-channel SARinterferometry. The polarimetric coherent...

Slope instabilities are one of the most important geo-hazards in terms of socio-economic costs. The island of La Réunion (Indian Ocean) is affected by constant slope movements and huge landslides due to a combination of rough topography, wet tropical climate and its specific geological context. We show that remote sensing techniques (DifferentialSARInterferometry and correlation of optical images) provide complementary means to characterize landslides on a regional scale. The vegetation cover generally hampers the analysis of C-band interferograms. We used JERS-1 images to show that the L-band can be used to overcome the loss of coherence observed in Radarsat C-band interferograms. Image correlation was applied to optical airborne and SPOT 5 sensors images. The two techniques were applied to a landslide near the town of Hellbourg in order to assess their performance for detecting and quantifying the ground motion associated to this landslide. They allowed the mapping of the unstable areas. Ground displacement of about 0.5 m yr(-1) was measured.

The development of Differential Synthetic Aperture Radar Interferometry (D-InSAR), in terms of its evolution from classic to advanced forms, such as Least-Squares approach, Permanent Scatterer Interferometry, Small Baseline Subset, and Coherent Pixel Technique, is reviewed, describing concisely the main principles of each method and highlighting the difference and relationship between them. Applications of InSAR technology in China were then introduced, together with the obstacles to overcome and feasible strategies, such as integrating MERIS/MODIS data to compensate for the atmospheric effect and GPS, and multi-platform SAR data to make InSAR technique practical and operational under various conditions. The latest developments were then analyzed along with high-quality SAR data, available thanks to the newly launched high-tech satellites, TerraSAR-X, and Cosmo Sky-med, and conclusions were drawn about the main limitations of the technique.

Full Text Available We propose a technique to provide interferometry by combining multiple images of the same area. This technique differs from the multi-baseline approach in literature as (a it exploits all the images simultaneously, (b it performs a spectral shift preprocessing to remove most of the decorrelation, and (c it exploits distributed targets. The technique is mainly intended for DEM generation at centimetric accuracy, as well as for differentialinterferometry. The problem is framed in the contest of single-input multiple-output (SIMO channel estimation via the cross-relations (CR technique and the resulting algorithm provides significant improvements with respect to conventional approaches based either on independent analysis of single interferograms or multi-baselines phase analysis of single pixels of current literature, for those targets that are correlated in all the images, like for long-term coherent areas, or for acquisitions taken with a short revisit time (as those gathered with future satellite constellations.

The Western Nyainqentanglha Mountains locates in the southeastern center of the Inner Tibetan Plateau (ITP). Glaciers in this region are influenced by both the continental climate of Central Asia and the Indian Monsoon system. Their melting on the western slopes feeds the Nam Co Lake, which is the second largest endorheic lake in the ITP. The elevation of Nam Co Lake increased at a rate of 0.25 ± 0.12 m year- 1 from 2003 to 2009. In this study, aimed at quantifying the decadal glacier mass balance in the Western Nyainqentanglha Mountains and their increasing melting contribution to Nam Co Lake; we applied the differential Bistatic SARinterferometry method to five pairs of TanDEM CoSSC datasets observed between 2013 and 2014 and SRTM acquired in 2000. The mean annual mass loss rate was - 0.235 ± 0.127 m w.e. year- 1 for the entire range. The mass loss rate for the northwestern slope (inside the Nam Co Lake drainage basin) and the southeastern slope (outside the Nam Co Lake drainage basin) were - 0.268 ± 0.129 m w.e. year- 1 and ¬ 0.219 ± 0.126 m w.e. year- 1, respectively. Our results agree well with previous fieldwork at the Zhadang and Gurenhekou glaciers located on the northwestern and southeastern slopes. Debris-cover suppressed glacier downwasting to some extent. By presuming that all of the melted ice flows into the lake, the glaciers' melting contribution to Nam Co Lake's increasing water volume was approximately 10.50 ± 9.00% during the period between 2003 and 2009.

Full Text Available Due to their remoteness, altitude and harsh climatic conditions, little is known about the glaciological parameters of ice caps on the Tibetan Plateau (TP. This study presents an interferometrical approach aiming at surface elevation changes of Purogangri ice cap, located on the central TP. Purogangri ice cap covers an area of 397 ± 9.7 km2 and is the largest ice cap on the TP. Its behavior is determined by dry and cold continental climate suggesting a polar-type glacier regime. We employed data from the actual TerraSAR-X mission and its add-on for Digital Elevation Measurements (TanDEM-X and compare it with elevation data from the Shuttle Radar Topography Mission (SRTM. These datasets are ideal for this approach as both datasets feature the same wavelength of 3.1 cm and are available at a fine grid spacing. Similar snow conditions can be assumed since the data were acquired in early February 2000 and late January 2012. The trend in glacier extend was extracted using a time series of Landsat data. Our results show a balanced mass budget for the studied time period which is in agreement with previous studies. Additionally, we detected an exceptional fast advance of one glacier tongue in the eastern part of the ice cap between 1999 and 2011.

A digital elevation model (DEM) of an ice cap in Greenland has been generated from airborne SARinterferometry data, calibrated with a new algorithm, and compared with airborne laser altimetry profiles and carrier-phase differential GPS measurements of radar reflectors deployed on the ice cap...

This brief study introduces a partially working concept being developed at IT4Innovations supercomputer (HPC) facility. This concept consists of several modules that form a whole body of an efficient system for observation of terrain or objects displacements using satellite SARinterferometry (InSAR). A metadata database helps to locate data stored in various storages and to perform basic analyzes. A special database has been designed to describe Sentinel-1 data, on its burst level. Custom Se...

Polarimetric Synthetic Aperture Radar Interferometry (PolInSAR) has been extensively applied for forest parameter inversion over different frequencies and polarimetric conditions. So far, most research was based on full-pol SAR images with relatively small coverage. A spaceborne SAR system will have the potential for PolInSAR applications used for global forest monitoring. Spaceborne dual-pol SAR images usually have higher resolution and larger swath than full-pol mode. In this paper, forest height retrieval was attempted by PolInSAR from a L-band spaceborne dual-pol SAR pairs using HH and HV channels. The random volume over ground (RVoG) model was used to retrieve the height and the coherence optimization method was extended to the dual-pol PolInSAR, which makes use of polarimetry to enhance the quality of SAR interferograms. The three-stage process is also used in the dual-pol PolInSAR technique. Finally, the experimental test was performed for forest height estimation on the dual-pol L-band SAR data of the Saihanba forest acquired by the ALOS PALSAR sensor in 2009.

Interferometric synthetic aperture radar (INSAR) systems have already demonstrated that elevation maps can be generated rapidly with single pass airborne across-track interferometry systems (XTT), and satellite repeat track interferometry (RTT) techniques have been used to map both elevation and ...

Full Text Available We investigate multichannel imaging radar systems employing coherent combinations of polarimetry and interferometry (Pol-InSAR. Such systems are well suited for the extraction of bio- and geophysical parameters by evaluating the combined scattering from surfaces and volumes. This combination leads to several important differences between the design of Pol-InSAR sensors and conventional single polarisation SAR interferometers. We first highlight these differences and then investigate the Pol-InSAR performance of two proposed spaceborne SAR systems (ALOS/PalSAR and TerraSAR-L operating in repeat-pass mode. For this, we introduce the novel concept of a phase tube which enables (1 a quantitative assessment of the Pol-InSAR performance, (2 a comparison between different sensor configurations, and (3 an optimization of the instrument settings for different Pol-InSAR applications. The phase tube may hence serve as an interface between system engineers and application-oriented scientists. The performance analysis reveals major limitations for even moderate levels of temporal decorrelation. Such deteriorations may be avoided in single-pass sensor configurations and we demonstrate the potential benefits from the use of future bi- and multistatic SAR interferometers.

This paper develops a temporal decorrelation model for the bistatic synthetic aperture radar (BSAR) interferometry. The temporal baseline is one of the important decorrelation sources for the repeat-pass synthetic aperture radar (SAR) interferometry. The study of temporal decorrelation is chal enging, especial y for the bistatic configuration, since temporal decorrelation is related to the data acquisition geometry. To develop an appropriate theoretical model for BSAR interferometry, the existing models for monostatic SAR cases are extended, and the general BSAR geometry con-figuration is involved in the derivation. Therefore, the developed temporal decorrelation model can be seen as a general model. The validity of the theoretical model is supported by Monte Carlo simulations. Furthermore, the impacts of the system parameters and BSAR geometry configurations on the temporal decorrelation model are discussed briefly.

InSAR measurements can be significantly affected by the atmosphere when the radar signal propagates through the atmosphere since it varies with space and time. Great efforts have been made in recent years to better understand the properties of the tropospheric effects and to develop methods for mitigating these effects. By using the basic principles of InSAR, the quantitative analysis of ionospheric delay effects on topography and surface deformation have been introduced for the first time. The measurement errors can be related to the vertical ionospheric total electron content (vTEC). By using the ionospheric observations, the effects of temporal ionospheric variations on InSAR have been analyzed. The results indicate that the ionospheric variations with time, season, solar cycle and geomagnetic activities can compromise the effectiveness of InSAR for both the measurement of topography and surface determination. The repeat-pass SARinterferometry errors induced by ionosphere should be corrected by actual measurements.

TanDEM-X (TDX) enables to generate an interferometric coherence without temporal decorrelation effect that is the most critical factor for a successful Pol-InSAR inversion, as have recently been used for forest parameter retrieval. This paper presents mangrove forest height estimation only using single-pass/single-baseline/dual-polarization TDX data by means of new dual-Pol-InSAR inversion technique. To overcome a lack of one polarization in a conventional Pol- InSAR inversion (i.e. an underdetermined problem), the ground phase in the Pol-InSAR model is directly estimated from TDX interferograms assuming flat underlying topography in mangrove forest. The inversion result is validated against lidar measurement data (NASA's G-LiHT data).

Full Text Available In the past few years, SARInterferometry specially InSAR and D-InSAR were extensively used for deformation monitoring related applications. Due to temporal and spatial decorrelation in dense vegetated areas, effectiveness of InSAR and D-InSAR observations were always under scrutiny. Multi-temporal InSAR methods are developed in recent times to retrieve the deformation signal from pixels with different scattering characteristics. Presently, two classes of multi-temporal InSAR algorithms are available- Persistent Scatterer (PS and Small Baseline (SB methods. This paper discusses the Stanford Method for Persistent Scatterer (StaMPS based PS-InSAR and the Small Baselines Subset (SBAS techniques to estimate the surface deformation in Tehri dam reservoir region in Uttarkhand, India. Both PS-InSAR and SBAS approaches used sixteen ENVISAT ASAR C-Band images for generating single master and multiple master interferograms stack respectively and their StaMPS processing resulted in time series 1D-Line of Sight (LOS mean velocity maps which are indicative of deformation in terms of movement towards and away from the satellites. From 1D LOS velocity maps, localization of landslide is evident along the reservoir rim area which was also investigated in the previous studies. Both PS-InSAR and SBAS effectively extract measurement pixels in the study region, and the general results provided by both approaches show a similar deformation pattern along the Tehri reservoir region. Further, we conclude that StaMPS based PS-InSAR method performs better in terms of extracting more number of measurement pixels and in the estimation of mean Line of Sight (LOS velocity as compared to SBAS method. It is also proposed to take up a few major landslides area in Uttarakhand for slope stability assessment.

In the past few years, SARInterferometry specially InSAR and D-InSAR were extensively used for deformation monitoring related applications. Due to temporal and spatial decorrelation in dense vegetated areas, effectiveness of InSAR and D-InSAR observations were always under scrutiny. Multi-temporal InSAR methods are developed in recent times to retrieve the deformation signal from pixels with different scattering characteristics. Presently, two classes of multi-temporal InSAR algorithms are available- Persistent Scatterer (PS) and Small Baseline (SB) methods. This paper discusses the Stanford Method for Persistent Scatterer (StaMPS) based PS-InSAR and the Small Baselines Subset (SBAS) techniques to estimate the surface deformation in Tehri dam reservoir region in Uttarkhand, India. Both PS-InSAR and SBAS approaches used sixteen ENVISAT ASAR C-Band images for generating single master and multiple master interferograms stack respectively and their StaMPS processing resulted in time series 1D-Line of Sight (LOS) mean velocity maps which are indicative of deformation in terms of movement towards and away from the satellites. From 1D LOS velocity maps, localization of landslide is evident along the reservoir rim area which was also investigated in the previous studies. Both PS-InSAR and SBAS effectively extract measurement pixels in the study region, and the general results provided by both approaches show a similar deformation pattern along the Tehri reservoir region. Further, we conclude that StaMPS based PS-InSAR method performs better in terms of extracting more number of measurement pixels and in the estimation of mean Line of Sight (LOS) velocity as compared to SBAS method. It is also proposed to take up a few major landslides area in Uttarakhand for slope stability assessment.

Interferometric synthetic aperture radar (INSAR) systems have already demonstrated that elevation maps can be generated rapidly with single pass airborne across-track interferometry systems (XTT), and satellite repeat track interferometry (RTT) techniques have been used to map both elevation...... and perturbations of the surface of the Earth. The Danish Center for Remote Sensing (DCRS) has experimented with airborne INSAR since 1993. Multiple track data are collected in a special mode in which the radar directly steers the aircraft which allows for very precise control of the flight path. Such data sets...... have been acquired at both L- and C-band. During 1994/95 the system was further modified to add the capability to perform single pass interferometric data acquisitions at C-band. This paper will discuss: (1) the general principles of INSAR systems and their application to topographic mapping and (2...

A Study involving GPS and differentialSARinterferometry (DInSAR) monitoring is developed to investigate a subsidence phenomenon in Aguascalientes valley and to obtain displacement models concerned with risk management applications and geodetic purposes. DInSAR study with archived Envisat data allows accumulated displacement mapping yearly, and recent TerraSAR-X data implementation provides a more accurate estimation of displacements, which is used for developing models to correct geodetic positions. The maximum subsidence rate calculated is 15 cm/year with a decreasing rate throughout time in some areas.

The Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard the Advanced Land Observing Satellite- 2 (ALOS-2, "DAICHI-2") is the latest L-band spaceborne synthetic aperture radar (SAR). PALSAR-2 observes the world mainly with 10 m resolution / 70 km swath Stripmap mode and 25 m resolution / 350 km swath ScanSAR mode. The 3-m resolution Stripmap mode is mainly used upon Japan. 350 km ScanSAR observation could detect large scale deformation e.g., the Mw 7.8 Gorkha, Nepal earthquake and its aftershocks in 2015. ALOS-2 ScanSAR is the first one that supports ScanSAR-ScanSARinterferometry in L-band spaceborne SAR. However, because of the parameter setting error for the orbit estimation, ALOS-2 PALSAR-2 ScanSAR could achieve little number of interferometric pair until the software modification on February 8, 2015. That is, the burst overlap timing required for the interferometric analysis was insufficient and it depends on the observation date. In this paper, we report the investigation results of this case and discuss the current status of the ALOS-2 ScanSAR InSAR. Some archives achieved before February 8, 2015 can be used for interferometric analysis with after Feb. 8. However, most of them have no interferometric pair. We also report that the archives acquired after February 8, have enough burst overlapping.

In this paper, the performance of median filter, elevation dependent adaptive sigma median filter, and directionally dependent adaptive sigma median filter are tested on both InSAR Tandem DEM and simulated high-level noisy DEM. Through the comparison, the directionally dependent adaptive sigma median filter is proved to be the most effective one not only in the noise removing but also in the boundary preserve.

The Bangkok Metropolitan region and its surrounding provinces are located in a low-lying delta plain of the Chao Phraya River. Extensive groundwater use from the late 1950s has caused the decline of groundwater levels in the aquifers and Holocene clay compaction beneath the Bangkok Region, resulting in significant subsidence of the ground. This ground deformation has been monitored using leveling surveys since 1978, and differential InSAR (Interferometric Synthetic Aperture Radar) analysis. It shows that the Bangkok Metropolitan region is subsiding at a rate of about 20 mm/year during the recent years due to law-limited groundwater pumping, although the highest subsidence rate as high as 120 mm/year was recorded in 1981. The subsidence rate in the Bangkok area has significantly decreased since the late 1980s; however, the affected area has spread out to the surrounding areas. The maximum subsidence rate up to 30 mm/year occurred in the outlying southeast and southwest coastal zones in 2002. In this study, we apply a SARinterferometry time series analysis to monitor ground deformations in the lower Chao Phraya delta plain (Lower Central Plain), Thailand, using ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band SAR) data acquired between July 2007 and September 2010. We derive a single reference time series interferogram from the stacking of unwrapped phases under the assumptions that those phases are smoothly and continuously connected, and apply a smoothness-constrained inversion algorithm that optimizes the displacement from the phase unwrapping of multitemporal differentialSAR interferograms. The SARinterferometry time series analysis succeeds to monitor the incremental line-of-sight (LOS)-change between SAR scene acquisitions. LOS displacements are converted to vertical displacements, based on the assumption that the ground displacement in this area occurs only in the vertical directions. This reveals an overall pattern of subsidence

Synthetic aperture radar interferometry (InSAR) can gain three-dimensional topography with high spatial resolution and height accuracy using across track interferometry[1]. Conventional InSAR produce three-dimensional images from SAR data. But when the working wavelength transit from microwave to optical wave, the transmission antenna and receive antenna become very sensitive to platform vibration and beam quality[2]. Through differential receive antenna formation, we can relax the requirement of platform and laser using synthetic aperture imaging ladar (SAIL) concept[3]. Line-of-sight motion constraints are reduced by several orders of magnitude. We introduce two distinctive forms of antenna formation according to the position of interferogram. The first architecture can simplify the interferogram processing and phase extraction algorithm under time-division multiplex operation. The second architecture can process the 2D coordinate and height coordinate at the same time. Using optical diffraction theory, a systematic theory of side-looking SAIL is mathematically formulated and the necessary conditions for assuring a correct phase history are established[4]. Based on optical transformation and regulation of wavefront, a side-looking SAIL of two distinctive architectures is invented and the basic principle, systematic theory, design equations and necessary conditions are presented. It is shown that high height accuracy can be reached and the influences from atmospheric turbulence and unmodeled line-of-sight motion can be automatically compensated.

This paper presents two examples of application of Synthetic Aperture Radar (SAR) interferometry (InSAR) to typical geomorphological problems. The principles of InSAR are introduced, taking care to clarify the limits and the potential of this technique for geomorphological studies. The application of InSAR to the quantification of landform attributes such as the slope and to the estimation of landform variations is investigated. Two case studies are presented. A first case study focuses on the problem of measuring landform attributes by interferometric SAR data. The interferometric result is compared with the corresponding one obtained by a Digital Elevation Model (DEM). In the second case study, the use of InSAR for the estimation of landform variations caused by a landslide is detailed.

Wideband SAR systems such as TerraSAR-X allow estimation of the absolute interferometric phase without resorting to error prone phase unwrapping. This is achieved through the delta-k technique that exploits frequency diversity within the range bandwidth to simulate a SAR system with a much longer carrier wavelength. This benefits all interferometric applications including DEM generation and land surface motion determination. Here we present the results of an ESA study (21318/07/NL/HE) into using delta-k absolute phase estimation for DEM generation and PSI (Persistent Scatterer Interferometry). Using TerraSAR- X data, examples from a delta-k DEM generation system are shown which avoid the errors induced by conventional phase unwrapping. For PSI, the possibilities of absolute phase estimation for a single PS are explored in theory and examples where wideband estimation is compared to conventional PSI processing for a stack of acquisitions over Paris.

The forest height is an important forest resource information parameter and usually used in biomass estimation. Forest height extraction with PolInSAR is a hot research field of imaging SAR remote sensing. SARinterferometry is a well-established SAR technique to estimate the vertical location of the effective scattering center in each resolution cell through the phase difference in images acquired from spatially separated antennas. The manipulation of PolInSAR has applications ranging from climate monitoring to disaster detection especially when used in forest area, is of particular interest because it is quite sensitive to the location and vertical distribution of vegetation structure components. However, some of the existing methods can't estimate forest height accurately. Here we introduce several available inversion models and compare the precision of some classical inversion approaches using simulated data. By comparing the advantages and disadvantages of these inversion methods, researchers can find better solutions conveniently based on these inversion methods.

Polarimetric Synthetic Aperture Radar Interferometry (Pol-InSAR) is an active radar remote sensing technique based on the coherent combination of both polarimetric and interferometric observables. The Pol-InSAR technique provided a step forward in quantitative forest parameter estimation. In the last decade, airborne SAR experiments evaluated the potential of Pol-InSAR techniques to estimate forest parameters (e.g., the forest height and biomass) with high accuracy over various local forest test sites. This dissertation addresses the actual status, potentials and limitations of Pol-InSAR inversion techniques for 3-D forest parameter estimations on a global scale using lower frequencies such as L- and P-band. The multi-baseline Pol-InSAR inversion technique is applied to optimize the performance with respect to the actual level of the vertical wave number and to mitigate the impact of temporal decorrelation on the Pol-InSAR forest parameter inversion. Temporal decorrelation is a critical issue for successful Pol-InSAR inversion in the case of repeat-pass Pol-InSAR data, as provided by conventional satellites or airborne SAR systems. Despite the limiting impact of temporal decorrelation in Pol-InSAR inversion, it remains a poorly understood factor in forest height inversion. Therefore, the main goal of this dissertation is to provide a quantitative estimation of the temporal decorrelation effects by using multi-baseline Pol-InSAR data. A new approach to quantify the different temporal decorrelation components is proposed and discussed. Temporal decorrelation coefficients are estimated for temporal baselines ranging from 10 minutes to 54 days and are converted to height inversion errors. In addition, the potential of Pol-InSAR forest parameter estimation techniques is addressed and projected onto future spaceborne system configurations and mission scenarios (Tandem-L and BIOMASS satellite missions at L- and P-band). The impact of the system parameters (e.g., bandwidth

spectral windows of the “Natural Electromagnetic Spectrum (NES)” pertinent to Remote Sensing; ( ii ) mitigating against common “Radio Frequency...122], the DLR E-SAR [223], the ONERA RAMSES SAR [70], and we refer to pertinent papers presented at recent expert meetings for additional details [66...amplitude and 1º in polarimetric phase; must possess a very high dynamic range; ( ii ) they must become extra-wide-band, covering the HF to EHF frequency

This study is aimed at exploring the potentials of SARInterferometry (InSAR) to aid Unmanned Aerial Vehicles (UAV) navigation. The basic idea is to infer both position and attitude of an aerial platform by inspecting the InSAR phase derived by a real time SAR interferometer mounted onboard the platform. Thanks to the expected favorable conditions in terms of geometrical sensitivity as well as signal coherence, the InSAR phase field can be used to derive the terrain elevation. By using both approximated position and attitude values of the platform as well as a reference Digital Terrain Model (DTM) from a mission database available onboard, it is possible to generate a synthetic InSAR phase model to be compared w.r.t. that derived by SAR observations. The geometrical transformation needed to match these two terrain models depends on the difference between position and attitude values derived by the instruments available on board and their actual values. Hence, this matching provides a feedback to be used for adjusting position and attitude. In order to assess the reliability of the proposed approach, we evaluated the interferometric sensitivity to changes in position and attitude. This analysis defines the limits of applicability of the InSAR-based approach and provides indications and requirements on geometric and radiometric parameters.

This paper concerns forest remote sensing using JPL's multi-baseline polarimetric interferometric UAVSAR data. It presents exemplary results and analyzes the possibilities and limitations of using SAR Tomography and Polarimetric SARInterferometry (PolInSAR) techniques for the estimation of forest structure. Performance and error indicators for the applicability and reliability of the used multi-baseline (MB) multi-temporal (MT) PolInSAR random volume over ground (RVoG) model are discussed. Experimental results are presented based on JPL's L-band repeat-pass polarimetric interferometric UAVSAR data over temperate and tropical forest biomes in the Harvard Forest, Massachusetts, and in the La Amistad Park, Panama and Costa Rica. The results are partially compared with ground field measurements and with air-borne LVIS lidar data.

This paper concerns forest remote sensing using JPL's multi-baseline polarimetric interferometric UAVSAR data. It presents exemplary results and analyzes the possibilities and limitations of using SAR Tomography and Polarimetric SARInterferometry (PolInSAR) techniques for the estimation of forest structure. Performance and error indicators for the applicability and reliability of the used multi-baseline (MB) multi-temporal (MT) PolInSAR random volume over ground (RVoG) model are discussed. Experimental results are presented based on JPL's L-band repeat-pass polarimetric interferometric UAVSAR data over temperate and tropical forest biomes in the Harvard Forest, Massachusetts, and in the La Amistad Park, Panama and Costa Rica. The results are partially compared with ground field measurements and with air-borne LVIS lidar data.

Space-borne SARDifferentialInterferometry (DInSAR) techniques are attractive for landslide investigations because of their capability to provide regional scale coverage and, under favourable conditions, spatially dense information on small ground surface deformations. In particular, advanced multi-temporal InSAR techniques such as Persistent Scatterer Interferometry (PSI) allow detecting and monitoring, with millimetre precision, displacements occurring on selected radar targets (PS) exhibiting coherent radar backscattering properties. PS targets correspond mainly to man-made structures or to rock outcrops, and their spatial density depends on the ground coverage, and it is maximum over urban areas. The application of multi-temporal InSAR analysis to slope instability monitoring poses challenges related to the complex kinematics of the phenomenon, as well as to the unfavourable settings of the area affected by landslides, often occurring on sites of limited extension, characterized by steep topography and variable vegetation cover. This is the case of the Daunia region, located in the Southern Italian Apennine Mountains, which is characterised by scarce urbanisation (mainly small hill-top towns) and dense vegetation cover. The SPINUA (Stable Point INterferometry over Un-urbanised Areas) PSI multi-temporal processing technique was used in the past years to detect and measure ground displacements over this region. Both C-band medium resolution SAR data from ERS-1/2 and ENVISAT ESA satellites, and X-band high resolution SAR data from the TerraSAR-X (TSX) satellite were used. Results indicate that PSI can be profitably used to investigate slope instability, mainly over the urban and peri-urban areas, and that, on these sites, TSX data result very promising for monitoring areas where ERS/ENVISAT PS density is too low. Nevertheless, the application of PSI for slope instability monitoring still remain problematic or impossible in rural and mountainous areas. This is the

Monitoring is a necessary task for infrastructure projects. Ground-based synthetic aperture radar (GB-SAR) has been used in a large variety of displacement measurements. However, it has not yet been applied as a monitoring tool during construction projects. This paper aims to demonstrate that GB-SAR can be very helpful for understanding the mechanisms that control structure deformations and for identifying unexpected events and sensitive areas during construction projects. This could be done in a cost-effective way, which complements the traditional displacement measurements. An experiment was performed in the future railway station of La Sagrera, Barcelona (Spain) to demonstrate the utility of GB-SAR on structure monitoring during construction projects. In this experiment, GB-SAR precisely quantified wall displacements induced by dewatering. Manual data and numerical models have been used to confirm the measurements with a correlation analysis and by comparing measurements and deformation patterns, which have produced similar results. These results validate the use of the GB-SAR technique as a monitoring tool during construction projects.

The development of efficient and cost-effective landslide monitoring techniques is the central aim of the alpEWAS research project (www.alpewas.de). Within the scope of the project a terrestrial geosensor network on a landslide site in the Bavarian Alps has been set up, consisting of low cost GNSS with subcentimeter precision, time domain reflectometry (TDR) and video tacheometry (VTPS). To increase the spatial sampling, 16 low-cost Radar Corner Reflectors (CRs) were installed on the site in 2011. The CRs are to reflect radar signals back to the TerraSAR-X radar satellite, allowing for precise displacement measurements. The subject of this study is the application of the CR SARInterferometry (CRInSAR) technique, and the integration of the derived motion field into an early warning system for landslide monitoring based on terrestrial measurements. An accurate validation data set is realized independently of the monitoring network using millimeter precision GNSS and tacheometer measurements. The 12 CRs from Astrium Geo-Information Services employed over the test site were specifically designed for TerraSAR-X satellite passes. They are made of concrete with integrated metal plates weighing about 80 to 100 kg. They are of triangular trihedral shape with minimal dimensions to obtain a Radar Cross Section 100 times stronger than that of the surrounding area. The concrete guarantees stability against harsh weather conditions, and robustness with respect to vandalism or theft. In addition, the Technical University of Munich (TUM) and the German Aerospace Center (DLR) installed another four CRs made entirely out of aluminum, with the TUM reflectors being of similar minimum size than the Astrium reflectors. Three CRs were placed on assumed stable ground outside the slope area and shall act as reference reflectors. Since the installation date of most CRs (25/08/2011), TerraSAR-X HighResolution SpotLight data have been repeatedly acquired from ascending orbit over the test

Multi-temporal InSAR (MTI) methods are effective tools for monitoring and investigating surface displacement on Earth based on conventional radar interferometry. These techniques allow us to measure deformation with uncertainties up to one millimeter per year, interpreting time series of interferometric phases at coherent/stable point scatterers. Considering the regular revisit time and wide-area coverage of satellite radar sensors, and that stable points usually correspond to buildings and o...

Atom interferometer (AI) based sensors exhibit precision and accuracy unattainable with classical sensors, thanks to the inherent stability of atomic properties. Dual atomic sensors operating in a differential mode further extend AI applicability beyond environmental disturbances. Extraction of the phase difference between dual AIs, however, typically introduces uncertainty and systematic in excess of that warranted by each AI's intrinsic noise characteristics, especially in practical applications and real time measurements. In this presentation, we report our efforts in developing practical schemes for reducing noises and enhancing sensitivities in the differential AI measurement implementations. We will describe an active phase extraction method that eliminates the noise overhead and demonstrates a performance boost of a gravity gradiometer by a factor of 3. We will also describe a new long-baseline approach for differential AI measurements in a laser ranging assisted AI configuration. The approach uses well-developed AIs for local measurements but leverage the mature schemes of space laser interferometry for LISA and GRACE. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a Contract with NASA.

The coseismic deformation produced by 1998 earthquake (Ms = 6.2) in Zhangbei-Shangyi of northern China is measured by the differential synthetic aperture radar interferometry (D-InSAR) technique using the European Remote Sensing satellite (ERS) SAR data. Interferograms are constructed from the ERS-1/2 SAR data by the three-pass method. The line-of-sight displacement map indicates that the deformation center of the earthquake is located at E114°20′,N40°57′,with the maximum uplift of 25 cm. The extent of the displacement is around 300 km2. The focal mechanism and earthquake-induced structures are analyzed based on the spatial distribution of the deformation. The results give new insights into the seismic mechanism study.

Tannia Mayorga Torres1,21 Universidad Central del Ecuador. Faculty of Geology, Mining, Oil, and Environment 2 Hubert H. Humphrey Fellowship 2015-16 IntroductionLandslides lead to human and economic losses across the country, mainly in the winter season. On the other hand, satellite radar data has cost-effective benefits due to open-source software and free availability of data. With the purpose of establishing an early warning system of landslide-related surface deformation, three case studies were designed in the Coast, Sierra (Andean), and Oriente (jungle) regions. The objective of this work was to assess the capability of L-band InSAR to get phase information. For the calculation of the interferograms in Repeat Orbit Interferometry PACkage, the displacement was detected as the error and was corrected. The coherence images (Figure 1) determined that L-band is suitable for InSAR processing. Under this frame, as a first approach, the stacking DInSAR technique [1] was applied in the case studies [2]; however, due to lush vegetation and steep topography, it is necessary to apply advanced InSAR techniques [3]. The purpose of the research is to determine a pattern of data acquisition and successful results to understand the spatial and temporal ground movements associated with landslides. The further work consists of establishing landslide inventories to combine phases of SAR images to generate maps of surface deformation in Tumba-San Francisco and Guarumales to compare the results with ground-based measurements to determine the maps' accuracy. References[1] Sandwell D., Price E. (1998). Phase gradient approach to stacking interferograms. Journal of Geophysical Research, Vol. 103, N. B12, pp. 30,183-30,204. [2] Mayorga T., Platzeck G. (2014). Using DInSAR as a tool to detect unstable terrain areas in an Andes region in Ecuador. NH3.5-Blue Poster B298, Vol. 16, EGU2014-16203. Austria. [3] Wasowski J., Bovenga F. (2014). Investigating landslides and unstable slopes with

Full Text Available The forest height is an important forest resource information parameter and usually used in biomass estimation. Forest height extraction with PolInSAR is a hot research field of imaging SAR remote sensing. SARinterferometry is a well-established SAR technique to estimate the vertical location of the effective scattering center in each resolution cell through the phase difference in images acquired from spatially separated antennas. The manipulation of PolInSAR has applications ranging from climate monitoring to disaster detection especially when used in forest area, is of particular interest because it is quite sensitive to the location and vertical distribution of vegetation structure components. However, some of the existing methods can’t estimate forest height accurately. Here we introduce several available inversion models and compare the precision of some classical inversion approaches using simulated data. By comparing the advantages and disadvantages of these inversion methods, researchers can find better solutions conveniently based on these inversion methods.

Help of satellite radar interferometry for urban subsidence observation has been demonstrated for several years now. This monitoring tool is able to provide an assessment of the ground motion with a millimetric accuracy and a large spatial coverage. We present here a result of this technique applied to the monitoring of a small area : the shopping centre complex and cinema multiplex in Marseilles, France. This construction work was one of the most important construction site of this last few years in France. Inaugurated in October, 1997, the multiplex had to close 6 of its 15 cinemas five months later because of collapsing risks due to important ground movements. It has been totally closed in July, 1999. The multiplex building demolition is currently under way. Finally, this "flop" represents a cost of 30 millions euros. 14 ERS images acquired between 1992 and 2000 had been processed in order to produce a set of 105 differential interferograms. We performed a recursive correction of orbital and topographic fringes using a FFT computation and a Digital Elevation Model provided by the French National Institute (IGN). The analysis of the interferograms series has allowed to detect unambiguously a signature of few pixels corresponding to the ground movement. From this study, we observed a ground deformation during 1997 to 1998, an overall stability during late 1998 to 1999 and again a deformation during late 1999 to 2000. This study shows that, in specific cases, traditional InSAR is able to provide valuable information on very localised ground deformation. It also shows the interest of a comprehensive study of the full ERS archive of this site in order to assess the stability of the ground before, when no ground-based measurements were available, during, and after the construction works.

The "Major Project Pompeii" (MPP) is a great collective commitment of different institututions and people to set about solving the serious problem of conservation of the largest archeological sites in the world. The ancient city of Pompeii with its 66 hectares, 44 of which are excaveted, is divided into 9 regiones (district), subdivided in 118 insulae (blocks) and almost 1500 domus (houses), and is Unesco site since 1996. The Italian Ministry for Heritage and Cultural Activities and Tourism (MiBACT) and Finmeccanica Group have sealed an agreement whereby the Finmeccanica Group will donate innovative technologies and services for monitoring and protecting the archaeological site of Pompeii. Moreover, the Italian Institute for Environment Protection and Research (ISPRA) - Geological Survey of Italy, was also involved to support the ground based analysis and interpretation of the measurements provided by the industrial team, in order to promote an interdisciplinary approach. In this work, we will focus on ground deformation measurements obtained by satellite SARinterferometry and on their interpretation. The satellite monitoring service is based on the processing of COSMO-SkyMed Himage data by the e-Geos proprietary Persistent Scatterer Pair (PSP) SARinterferometry technology. The PSP technique is a proven SARinterferometry method characterized by the fact of exploiting in the processing only the relative properties between close points (pairs) in order to overcome atmospheric artifacts (which are one of the main problems of SARinterferometry). Validations analyses showed that this technique applied to COSMO-SkyMed Himage data is able to retrieve very dense (except of course on vegetated or cultivated areas) millimetric deformation measurements with sub-metric localization. By means of the COSMO-SkyMed PSP SARinterferometry processing, a historical analysis of the ground and structure deformations occurred over the entire archaeological site of Pompeii in the

Synthetic aperture radar (SAR) interferometry is a powerful technology for detection and monitoring of slow ground surface movements. Monitoring of ground deformations in mining structures is an important application, particularly difficult because the scene changes with time. The persistent scatterer pair (PSP) approach, recently proposed to overcome some limitations of standard persistent scatter interferometry, proved to be effective also for mine monitoring. In this work, after resuming the main ideas of the PSP method, we describe the PSP measurements obtained from high- resolution X-band COSMO-SkyMed data over a large mining area in Minas Gerais state, Brazil. The outcomes demonstrate that dense and accurate ground deformation measurements can be obtained on the mining area and its structures (such as open pits, waste dumps, conveyor belts, water and tailings dams, etc.), achieving a consistent global view including also areas where field instruments are not installed.

Archaeological sites and cultural heritage are considered as critical assets for the society, representing not only the history of region or a culture, but also contributing to create a common identity of people living in a certain region. In this view, it is becoming more and more urgent to preserve them from climate changes effect and in general from their degradation. These structures are usually just as precious as fragile: remote sensing technology can be useful to monitor these treasures. In this work, we will focus on ground deformation measurements obtained by satellite SARinterferometry and on the methodology adopted and implemented in order to use the results operatively for conservation policies in a Italian archaeological site. The analysis is based on the processing of COSMO-SkyMed Himage data by the e-GEOS proprietary Persistent Scatterer Pair (PSP) SARinterferometry technology. The PSP technique is a proven SARinterferometry technology characterized by the fact of exploiting in the processing only the relative properties between close points (pairs) in order to overcome atmospheric artefacts (which are one of the main problems of SARinterferometry). Validations analyses [Costantini et al. 2015] settled that this technique applied to COSMO-SkyMed Himage data is able to retrieve very dense (except of course on vegetated or cultivated areas) millimetric deformation measurements with sub-metric localization. Considering the limitations of all the interferometric techniques, in particular the fact that the measurement are along the line of sight (LOS) and the geometric distortions, in order to obtain the maximum information from interferometric analysis, both ascending and descending geometry have been used. The ascending analysis allows selecting measurements points over the top and, approximately, South-West part of the structures, while the descending one over the top and the South-East part of the structures. The interferometric techniques needs

This study analyzes the main phase contributions of ScanSAR-Stripmap interferometry and further points out the special component caused by unsynchronized echoes,which is then verified in the experiment.The whole process of ScanSARStripmap interferometry has been proposed and implemented with the help of relating modules of the Repeat Orbit Interferometry Package (ROI_PAC) developed by Jet Propulsion Laboratory (JPL).Coregistration and improvement of coherence are solved emphatically.Finally,ScanSAR-Stripmap interferometry is realized using Envisat ASAR data and the results are compared with those of traditional Stripmap-Stripmap interferometry for validation.%分析了ScanSAR-Stripmap干涉测量的相位组成,指出其因非同步数据引起的特有相位项,并通过实验验证了该相位项的存在.提出一整套ScanSAR-Stripmap干涉测量方法,借助JPL开发的开源干涉测量软件ROI_PAC的相应模块实现干涉处理过程,重点解决了ScanSAR-Stripmap两种模式数据间的配准以及相干性的提高等问题.用Envisat ASAR数据验证了该方法的可行性.最后将实验结果同常规条带式干涉测量结果做了对比与分析,验证了该方法的正确性.

Ground subsidence is one of the key factors damaging transportation facilities, e.g., road networks consisting of highways and railways. In this paper, we propose to apply the persistent scatterer synthetic aperture radar interferometry (PS-InSAR) approach that uses high-resolution TerraSAR-X (TSX) imagery to extract the regional scale subsidence rates (i.e., average annual sub-sidence in mm/year) along road networks. The primary procedures involve interferometric pair selection, interfer-ogram generation, persistent scatterer (PS) detection, PS networking, phase parameterization, and subsidence rate estimation. The Xiqing District in southwest Tianjin (China) is selected as the study area. This district contains one railway line and several highway lines. A total of 15 TSX images covering this area between April 2009 and June 2010 are utilized to obtain the subsidence rates by using the PS-InSAR (PSI) approach. The subsidence rates derived from PSI range from -68.7 to -1.3 mm/year. These findings show a significantly uneven subsidence pattern along the road network. Comparison between the PSI-derived subsidence rates and the leveling data obtained along the highways shows that the mean and standard deviation (SD) of the discrepancies between the two types of subsidence rates are 0.1 and ±3.2 mm/year, respec-tively. The results indicate that the high-resolution TSX PSI is capable of providing comprehensive and detailed subsidence information regarding road networks with millimeter-level accuracy. Further inspections under geo-logical conditions and land-use categories in the study area indicate that the observed subsidence is highly related to aquifer compression due to groundwater pumping. There-fore, measures should be taken to mitigate groundwater extraction for the study area.

The development and application of the “digital mine” concept in China depends heavily upon the use of remote sensing data as well as domestic expertise and awareness.Illegal mining of mineral resources has been a serious long term problem frustrating the Xishimen Iron Ore Mine management.This mine is located in Wu'an county in Hebei province,China.Illegal activities have led to enormous economic losses by interfering with the normal operation of the Xishimen mine and have ruined the surrounding environment and the stability of the Mahe riverbed the crosses the mined area.This paper is based on field reconnaissance taken over many years around the mine area.The ground survey data are integrated with Differential Synthetic Aperture Radar Interferometry (D-InSAR) results from ALOS/PALSAR data to pinpoint mining locations.By investigating the relationship between the resulting interferometric deformation pattern and the mining schedule,which is known a priori,areas affected by illegal mining activities are identified.To some extent these areas indicate the location of the illegal site.The results clearly demonstrate D-InSAR's ability to cost-effectively monitor illegal mining activities.

Synthetic Aperture Radar Interferometry (InSAR) is a powerful tool to measure surface deformation and is well suited for surveying active volcanoes using historical and existing satellites. However, the value and applicability of InSAR for geodynamic monitoring problems is limited by the influence of temporal decorrelation and electromagnetic path delay variations in the atmosphere, both of which reduce the sensitivity and accuracy of the technique. The aim of this PhD thesis research is: how to optimize the quantity and quality of deformation signals extracted from InSAR stacks that contain only a low number of images in order to facilitate volcano monitoring and the study of their geophysical signatures. In particular, the focus is on methods of mitigating atmospheric artifacts in interferograms by combining time-series InSAR techniques and external atmospheric delay maps derived by Numerical Weather Prediction (NWP) models. In the first chapter of the thesis, the potential of the NWP Weather Research & Forecasting (WRF) model for InSAR data correction has been studied extensively. Forecasted atmospheric delays derived from operational High Resolution Rapid Refresh for the Alaska region (HRRR-AK) products have been compared to radiosonding measurements in the first chapter. The result suggests that the HRRR-AK operational products are a good data source for correcting atmospheric delays in spaceborne geodetic radar observations, if the geophysical signal to be observed is larger than 20 mm. In the second chapter, an advanced method for integrating NWP products into the time series InSAR workflow is developed. The efficiency of the algorithm is tested via simulated data experiments, which demonstrate the method outperforms other more conventional methods. In Chapter 3, a geophysical case study is performed by applying the developed algorithm to the active volcanoes of Unimak Island Alaska (Westdahl, Fisher and Shishaldin) for long term volcano deformation

Full Text Available This paper analyses the possibility of using a fifth passive satellite for endowing the Italian COSMO-SkyMed constellation with cross- and along-track SAR interferometric capabilities, by using simultaneously flying and operating antennas. Fundamentals of developed models are described and potential space configurations are investigated, by considering both formations operating on the same orbital plane and on separated planes. The study is mainly aimed at describing achievable baselines and their time histories along the selected orbits. The effects of tuning orbital parameters, such as eccentricity or ascending node phasing, are pointed out, and simulation results show the most favorable tandem configurations in terms of achieved baseline components, percentage of the orbit adequate for interferometry, and covered latitude intervals.

Dikes are the main man made structures in flood protection systems for the protection of humans and economic values. Usually dikes are built with a sandy core and clay or concrete layer covering the core. Thus, dikes are prone to a vertical shrinkage due to soil physical processes such as reduction of pore space and gravity increasing the risk of a crevasse during floods. In addition, this vulnerability is amplified by a sea level rise due to climate change. To guarantee the stability of dikes, a labourer intensive program is carried out by national authorities monitoring the dikes by visual inspection. In the presented study, a quantitative approach is presented using SARInterferometry for the monitoring of the stability of dikes from space. In particular, the vertical movement of dikes due to shrinkage is monitored using persistent scatterer interferometry. Therefore three different types of dikes have been investigated: a sea coast dike with a concrete cover, a sea coast dike with short grass cover and a smaller river dike with grass cover. All dikes are located in Germany. Results show the potential of the monitoring technique as well as spatial differences in the stability of dikes with subsidence rates in parts of a dike up to 7 mm/a.

Two ascending European Space Agency (ESA) Earth Resources Satellites (ERS)-1/-2 tandem-mode, synthetic aperture radar (SAR) pairs are used to calculate the surface elevation of Hofsjokull, an ice cap in central Iceland. The motion component of the interferometric phase is calculated using the 30 arc-second resolution USGS GTOPO30 global digital elevation product and one of the ERS tandem pairs. The topography is then derived by subtracting the motion component from the other tandem pair. In order to assess the accuracy of the resultant digital elevation model (DEM), a geodetic airborne laser-altimetry swath is compared with the elevations derived from the interferometry. The DEM is also compared with elevations derived from a digitized topographic map of the ice cap from the University of Iceland Science Institute. Results show that low temporal correlation is a significant problem for the application of interferometry to small, low-elevation ice caps, even over a one-day repeat interval, and especially at the higher elevations. Results also show that an uncompensated error in the phase, ramping from northwest to southeast, present after tying the DEM to ground-control points, has resulted in a systematic error across the DEM.

We present a flow down error analysis from the radar system to topographic height errors for bi-static single pass SARinterferometry for a satellite tandem pair. Because of orbital dynamics the baseline length and baseline orientation evolve spatially and temporally, the height accuracy of the system is modeled as a function of the spacecraft position and ground location. Vector sensitivity equations of height and the planar error components due to metrology, media effects, and radar system errors are derived and evaluated globally for a baseline mission. Included in the model are terrain effects that contribute to layover and shadow and slope effects on height errors. The analysis also accounts for nonoverlapping spectra and the non-overlapping bandwidth due to differences between the two platforms' viewing geometries. The model is applied to a 514 km altitude 97.4 degree inclination tandem satellite mission with a 300 m baseline separation and X-band SAR. Results from our model indicate that global DTED level 3 can be achieved.

SARinterferometry has long been regarded as an effective tool for wide-area topographic mapping in hilly and mountainous areas. However, quality of InSAR DEM product is usually affected by atmospheric disturbances and decorrelation-induced voids, especially for data acquired in repeat-pass mode. In this paper, we proposed an approach for improved topographic mapping by optimal fusion of multi-orbit InSAR DEMs with correction of atmospheric phase screen (APS). An experimental study with highresolution TerraSAR-X and COSMO-SkyMed datasets covering a mountainous area was carried out to demonstrate the effectiveness of the proposed approach. Validation with a reference DEM of scale 1:50,000 indicated that vertical accuracy of the fused DEM can be better than 5 m.

The combination of natural, anthropogenic, and climate change impacts on the water resources of the Middle East and North Africa (MENA) region has devastated its water resources well beyond its current and projected populations. The increased exploitation of groundwater resources in the past half-century coupled with successive droughts has resulted in the acceleration of subsidence rates in the Souss and Massa basins in Morocco. We have completed a preliminary investigation of these impacts on the Souss and Massa basins (~27,000 km2) in the southwestern part of Morocco. This area is characterized by a semi-arid climate (annual precipitation 70-250 mm/year) with agriculture, tourism, and commercial fishing as the primary economic activities, all of which require availability of adequate freshwater resources. Additionally the primary groundwater aquifer (Plio-Quaternary Plain Aquifer), an unconfined aquifer formed mostly of sand and gravel, is being harvested by >20,000 wells at a rate of 650 MCM/yr., exceeding the rate of recharge by 260 MCM/year. Intense development over the past 50 years has exposed the aquifer to a serious risk of groundwater table drawdown (0.5m-2.5m/yr.), land subsidence, loss of artesian pressure, salinization, salt water intrusions along the coast, and deterioration of water quality across the watershed. DifferentialInterferometry Synthetique Aperture Radar (DInSAR) was utilized to measure ground subsidence induced by groundwater withdrawal. Land subsidence caused by excessive groundwater extraction was determined using a threefold methodology: (1) extraction of subsidence and land deformation patterns using radar interferometry, (2) correlation of the high subsidence areas within the basins to possible natural and anthropogenic factors (e.g. sea level rise, unconsolidated lithological formations distribution, urbanization, excessive groundwater extraction), and (3) forecasting the future of the Souss and Massa basins over the next century

The best visual expression of mountain permafrost are rockglaciers, which, in contrast to the permafrost itself, can be mapped and monitored directly using remotely sensed data. Studies carried out in various parts of the European Alps have shown surface acceleration of rockglaciers and even destabilization of several such landforms over the two last decades, potentially related to the changing permafrost creep conditions. Changes in rockglacier motion are therefore believed to be the most indicative short- to medium-term response of rockglaciers to environmental changes and thus an indicator of mountain permafrost conditions in general. The ESA DUE GlobPermafrost project develops, validates and implements EO products to support research communities and international organizations in their work on better understanding permafrost characteristics and dynamics. Within this project we are building up a worldwide long-term monitoring network of active rockglacier motion investigated using remote sensing techniques. All sites are analysed through a uniform set of data and methods, and results are thus comparable. In order to quantify the rate of movement and the relative changes over time we consider two remote sensing methods: (i) matching of repeat optical data and (ii) satellite radar interferometry. In this contribution, we focus on the potential of recent high spatial resolution SAR data for the analysis of periglacial processes in mountain environments with special attention to the Ile and Kungöy Ranges of Northern Tien Shan at the border between Kazakhstan and Kyrgyzstan, an area which contains a high number of large and comparably fast (> 1m/yr) rockglaciers and is of interest as dry-season water resource and source of natural hazards. As demonstrated in the past with investigations conducted in the Swiss Alps, the visual analysis of differentialSAR interferograms can be employed for the rough estimation of the surface deformation rates of rockglaciers and

In last years, Terrestrial Synthetic Aperture Radar Interferometry (TInSAR) became a key technology in the field of landslide and structures/infrastructures displacement monitoring. Thanks to undoubted advantages such as i) widespread information, ii) fully remote applicability over long ranges and iii) high accuracy, this technique promises to be a very effective solution for a lot of geological and engineering issues. Even if this technique was born for interferometric analyses (basing on the phase differences between SAR images collected at different time intervals), recent studies demonstrated its reliability also with non-interferometric processing approaches, based on the amplitude tracking of high-reflectivity objects (i.e. corner reflectors). Furthermore, both approaches can be used for both continuous and discontinuous monitoring, thus opening to a wide spectrum of applications for different purposes. The aim of this work is to provide information about the reliability and the accuracy of TInSAR technique in its different kind of applications. In the frame of this work, two case studies of landslides monitored with a continuous acquisition mode (about 5 minutes sampling rate) have been investigated. The first case study consists of superficial instability problems mainly related to huge rainfalls and works, leading to non-linear displacements up to 10 mm/day. In order to assess the impact of discontinuous acquisition mode, data subsampling of one data/day for an overall monitoring period of about 3 months has been performed. The comparison between discontinuous and continuous interferometric processing approach allowed the identification of some aliasing and ambiguity problems in the discontinuous approach, especially in periods when high displacement rates were affecting the slope. Nevertheless, in most of such cases, it was still possible to provide qualitative information about criticalities, even if a precise estimation of displacement entities was

Land subsidence has become the most common hazard in urban area that could led to cracking buildings and infrastructures, extending the flooding area or even change the river path. Despite deriving precise information, conventional subsidence monitoring techniques are considered as costly, man-power consuming and lack of comprehensive information. Recently, SARInterferometry (InSAR) has become a widely used geodetic technique for monitoring the deformation of the Earth's surface, especially methods based on the use of a multi-temporal dataset. In this study, we use a stack of 18 SAR images acquired from L-band PALSAR sensor onboard the ALOS satellite to derive the subsidence information of Ho Chi Minh city, Vietnam over the period of December 2006 to December 2010. The Stanford Method for Persistent Scatterers (StaMPS) Multi-Temporal Interferometry (MTI) approach is chosen to take advantages of both the persistent scatterers and the distributed scatterers, which could be used as monitoring points to measure the subsidence process. Assume the subsidence in this area mostly corresponds to vertical components, we found subsidence patterns along Saigon river and in the South of the city. Maximum subsidence rate reaches up to -66 mm/year in vertical direction. Finally, InSAR derived result and previous levelling data are taken into comparison to find the correlation between the two results.

Under the NASA ESTO sponsored Instrument Incubator Program we have designed a lightweight, reconfigurable polarimetric L-band SAR designed for repeat pass deformation measurements of rapidly deforming surfaces of geophysical interest such as volcanoes or earthquakes. This radar will be installed on an unmanned airborne vehicle (UAV) or a lightweight, high-altitude, and long endurance platform such as the Proteus. After a study of suitable available platforms we selected the Proteus for initial development and testing of the system. We want to control the repeat track capability of the aircraft to be within a 10 m tube to support the repeat deformation capability. We conducted tests with the Proteus using real-time GPS with sub-meter accuracy to see if pilots could fly the aircraft within the desired tube. Our results show that pilots are unable to fly the aircraft with the desired accuracy and therefore an augmented autopilot will be required to meet these objectives. Based on the Proteus flying altitude of 13.7 km (45,000 ft), we are designing a fully polarimetric L-band radar with 80 MHz bandwidth and 16 km range swath. This radar will have an active electronic beam steering antenna to achieve Doppler centroid stability that is necessary for repeat-pass interferometry (RPI). This paper will present are design criteria, current design and expected science applications.

The Augustine Volcano is a conical-shaped, active stratovolcano located on an island of the same name in Cook Inlet, about 290 km southwest of Anchorage, Alaska. Augustine has experienced seven significant explosive eruptions - in 1812, 1883, 1908, 1935, 1963, 1976, 1986, and in January 2006. To measure the ground surface deformation of the Augustine Volcano before the 2006 eruption, we applied satellite radar interferometry using Synthetic Aperture Radar (SAR) images from three descending and three ascending satellite tracks acquired by European Remote Sensing Satellite (ERS) 1 and 2 and the Environment Satellite (ENVISAT). Multiple interferograms were stacked to reduce artifacts caused by atmospheric conditions, and we used a singular value decomposition method to retrieve the temporal deformation history from several points on the island. Interferograms during 1992 and 2005 show a subsidence of about 1-3 cm/year, caused by the contraction of pyroclastic flow deposits from the 1986 eruption. Subsidence has decreased exponentially with time. Multiple interferograms between 1992 and 2005 show no significant inflation around the volcano before the 2006 eruption. The lack of a pre-eruption deformation signal suggests that the deformation signal from 1992 to August 2005 must have been very small and may have been obscured by atmospheric delay artifacts.

Led by the Italian Institute for Environmental Protection and Research, in collaboration with NERC British Geological Survey, Geological and Mining Institute of Spain, University of Milano-Bicocca and Cyprus University of Technology, the PROTHEGO project, co-funded in the framework of JPI on Cultural Heritage EU program (2015-2018), brings an innovative contribution towards the analysis of geo-hazards in areas of cultural heritage in Europe. The project apply InSAR techniques to monitor monuments and sites that are potentially unstable due to natural geo-hazard. After the remote sensing investigation, detailed geological interpretation, hazard analysis, local-scale monitoring, advanced modeling and field surveying for some case studies is implemented. The selected case studies are: the Alhambra in Granada (ES); the Choirokoitia village (CY); the Derwent Valley Mills (UK); the Pompei archaeological site and Historical centre of Rome (IT). In this work, in particular, we will focus on ground deformation measurements (obtained by satellite SARInterferometry) and on their interpretation with respect to the ancient Rome City Walls. The research activities carried out jointly with the Superintendence's technicians, foresee the implementation of a dedicated web GIS platform as a final repository for data storage and spatial data elaboration. The entire circuit of the ancient city walls (both Mura Aureliane and Mura Gianicolensi), was digitalized and georeferenced. All the elements (towers, gates and wall segments) were drawn and collected in order to produce a map of elements at risk. A detailed historical analysis (during the last twenty years) of the ground and structural deformations were performed. A specific data sheet of ruptures was created and fulfilled in order to produce a geographic inventory of past damage. This data sheet contains the following attributes: triggering data; typology of damage; dimension, triggering mechanism; presence of restoration works

Full Text Available Synthetic aperture radar (SAR has been an unparalleled tool in cloudy and rainy regions as it allows observations throughout the year because of its all-weather, all-day operation capability. In this paper, the influence of Wenchuan Earthquake on the Sichuan Giant Panda habitats was evaluated for the first time using SARinterferometry and combining data from C-band Envisat ASAR and L-band ALOS PALSAR data. Coherence analysis based on the zero-point shifting indicated that the deforestation process was significant, particularly in habitats along the Min River approaching the epicenter after the natural disaster, and as interpreted by the vegetation deterioration from landslides, avalanches and debris flows. Experiments demonstrated that C-band Envisat ASAR data were sensitive to vegetation, resulting in an underestimation of deforestation; in contrast, L-band PALSAR data were capable of evaluating the deforestation process owing to a better penetration and the significant coherence gain on damaged forest areas. The percentage of damaged forest estimated by PALSAR decreased from 20.66% to 17.34% during 2009–2010, implying an approximate 3% recovery rate of forests in the earthquake impacted areas. This study proves that long-wavelength SARinterferometry is promising for rapid assessment of disaster-induced deforestation, particularly in regions where the optical acquisition is constrained.

The regulation of the carbon cycle is a critical ecosystem service provided by forests globally. It is, therefore, necessary to have robust techniques for speedy assessment of forest biophysical parameters at the landscape level. It is arduous and time taking to monitor the status of vast forest landscapes using traditional field methods. Remote sensing and GIS techniques are efficient tools that can monitor the health of forests regularly. Biomass estimation is a key parameter in the assessment of forest health. Polarimetric SAR (PolSAR) remote sensing has already shown its potential for forest biophysical parameter retrieval. The current research work focuses on the retrieval of forest biophysical parameters of tropical deciduous forest, using fully polarimetric spaceborne C-band data with Polarimetric SARInterferometry (PolInSAR) techniques. PolSAR based Interferometric Water Cloud Model (IWCM) has been used to estimate aboveground biomass (AGB). Input parameters to the IWCM have been extracted from the decomposition modeling of SAR data as well as PolInSAR coherence estimation. The technique of forest tree height retrieval utilized PolInSAR coherence based modeling approach. Two techniques - Coherence Amplitude Inversion (CAI) and Three Stage Inversion (TSI) - for forest height estimation are discussed, compared and validated. These techniques allow estimation of forest stand height and true ground topography. The accuracy of the forest height estimated is assessed using ground-based measurements. PolInSAR based forest height models showed enervation in the identification of forest vegetation and as a result height values were obtained in river channels and plain areas. Overestimation in forest height was also noticed at several patches of the forest. To overcome this problem, coherence and backscatter based threshold technique is introduced for forest area identification and accurate height estimation in non-forested regions. IWCM based modeling for forest

One of the important consequences of climate change is the global sea level rise of 20cm since the end of the 19th century. This process is very likely to continue and accelerate in the future. Future projections of global sea level rise range from about 30cm to 80cm by 2100 with significant regional variability). Local and regional vertical ground motions are one of the important sources of uncertainties to consider in sea level rise impact assessments. However, it is very difficult, if not impossible, to evaluate them without observations due to their complex causes and evolution in space and time. Consequently, a first motivation to accurately characterize vertical ground motions in large coastal cities is to reduce the uncertainties of sea level rise impact assessments. A second challenge motivating a precise characterization of vertical ground motions in coastal cities is to reconcile sea level estimates for the 20th century: over this period, there is a slight disagreement between (1) observations of sea level rise obtained from the available tide gauge data sets, and (2) the sum of contributions from each process causing sea level rise. Accurate knowledge about the ground motions affecting tide gauges is thus highly desirable, especially in regions poorly covered by tide gauges. Indeed, one of the possible explanations of the 20th century sea level budget imbalance is an inappropriate spatial sampling of historical tide gauges along the oceans' coastlines, most being located in Europe and in the United States. In addition, noteworthy is the fact that Tide Gauges with long Time Series are generally located in urbanized areas. Growing of urbanizations in development during the last century can result in local changes of ground surface level (in particular: groundwater extraction produces subsidence phenomena). In this perspective, we propose the use of DifferentialSARinterferometry techniques for characterizing the ground surface deformation in the

For all the European Countries, the rail network represents a key critical infrastructure, deserving protection in view of its continuous structure spread over the whole territory, of the high number of European citizens using it for personal and professional reasons, and of the large volume of freight moving through it. Railway system traverses a wide variety of terrains and encounters a range of geo-technical conditions. The interaction of these factors together with climatic and seismic forcing, may produce ground instabilities that impact on the safety and efficiency of rail operations. In such context, a particular interest is directed to the development of technologies regarding both the prevention of mishaps of infrastructures and the fast recovery of their normal working conditions after the occurrence of accidents (disaster managing). Both these issues are of strategic interest for EU Countries, and in particular for Italy, since, more than other countries, it is characterized by a geo-morphological and hydro-geological structure complexity that increases the risk of natural catastrophes due to landslides, overflowings and floods. The present study has been carried out in the framework of a scientific project aimed at producing a diagnostic system, capable to foresee and monitor landslide events along railway networks by integrating in situ data, detected from on board sophisticated innovative measuring systems, with Earth Observation (EO) techniques. Particular importance is devoted to the use of advanced SARinterferometry, thanks to their all-weather, day-night capability to detect and measure with sub-centimeter accuracy ground surface displacements that, in such context, can occur before a landslide event or after that movements . Special attention is directed to the use of SAR images acquired by COSMO/SkyMed (ASI) constellation capable to achieve very high spatial resolution and very short revisit and response time. In this context, a stack of 57 CSK

In a typical interferometric synthetic aperture radar (IFSAR) system employed for terrain elevation mapping, terrain height is estimated from phase difference data obtained from two phase centers separated spatially in the cross-track direction. In this paper we show how the judicious design of a three phase center IFSAR renders phase unwrapping, i.e., the process of estimating true continuous phases from principal values of phase (wrapped modulo 2{pi}), a much simpler process than that inherent in traditional algorithms. With three phase centers, one IFSAR baseline can be chosen to be relatively small (two of the phase centers close together) so that all of the scene`s terrain relief causes less than one cycle of phase difference. This allows computation of a coarse height map without use of any form of phase unwrapping. The cycle number ambiguities in the phase data derived from the other baseline, chosen to be relatively large (two of the phase centers far apart), can then be resolved by reference to the heights computed from the small baseline data. This basic concept of combining phase data from one small and one large baseline to accomplish phase unwrapping has been previously employed in other interferometric problems, e.g., laser interferometry and direction-of-arrival determination from multiple element arrays, The new algorithm is shown to possess a certain form of immunity to corrupted interferometric phase data that is not inherent in traditional two-dimensional path-following phase unwrappers. This is because path-following algorithms must estimate, either implicity or explicity, those portions of the IFSAR fringe data where discontinuities in phase occur. Such discontinuties typically arise from noisy phase measurements derived from low radar return areas of the SAR imagery, e.g., shadows, or from areas of steep terrain slope.

This paper comprehensively describes the scientific research plan of the TanDEM -X/TerraSAR -X bistatic SAR mission, with emphasis placed on its scientific objectives, TanDEM-X satellite parameters, orbital configuration and data acquisition modes. Then, the advantages of the new InSAR techniques including bistatic SAR, Pol-InSAR and digital beam forming are briefly discussed and the progress of the techniques of TanDEM-X bistatic SARinterferometry is analyzed. These new SAR techniques will greatly promote the application potential of SARinterferometry in Earth sciences such as global topography mapping, glaciology, oceanography and geology.%较全面、系统地介绍了TanDEM-X/TerraSAR-X双站SAR科学计划，重点涉及其科学目标、TanDEM-X卫星参数、轨道结构以及干涉数据获取模式等相关内容，并讨论了双站SAR成像、极化InSAR和数字波束成形等干涉测量新技术及其研究进展。这些双站SAR新技术的实现将大大地推动SAR干涉测量在全球地形测绘、冰川学、海洋学及地质学等领域中的应用。

Measurement of flow velocity strain rate of a floating glacier is critical to the investigation of detailed flow regime and crevassing mechanism. We measured the surface deformation of Campbell Glacier Tongue (CGT) in East Antarctica from the 14 COSMO-SkyMed one-day tandem differential interferometric SAR (DInSAR) image pairs obtained in 2011. By removing the vertical tidal deflection obtained from the double-differential InSAR (DDInSAR) signals, we derived the tide-corrected ice-flow velocity and strain rate of CGT. The vertical tidal deflection of CGT was estimated by multiplying the tidal variations corresponding to the DInSAR images by the DDInSAR-derived tide deflection ratio, which was removed from the DInSAR signals to extract ice velocity only. The orientation of crevasses in CGT was nearly perpendicular to the direction of the most tensile strain rate calculated from the tide-corrected ice velocity. This demonstrates that the crevasses form by ice flow in respect of the DInSAR accuracy, not by tidal deflection. The tide correction of DInSAR signals over floating glaciers by using the DDInSAR-derived tide deflection ratio is useful for estimating accurate ice velocity and strain rate for analyzing crevasses. The tide-corrected ice velocity and strain rate will thus be of great value in a better understating of ice dynamics of floating glaciers. This research was funded by National Research Foundation of Korea (NRF-2016R1D1A1A09916630).

In this study, we analyze 25 RADARSAT-2 images from ascending and descending geometries to study the creep rate on the Hayward fault and landslide motions near Berkeley, CA. We applied a coherence optimization technique from polarimetric synthetic aperture radar interferometry (PolInSAR) to increase the accuracy of the measurements. We resolve 3-5 mm/year of motion along the Hayward fault, in agreement with earlier creep estimates. We identify a potential motion on secondary fault, northeast and parallel to the Hayward fault, which is creeping at a lower rate of ~1.5 mm/year. In addition, we identify a number of landslides along the hills east of the fault that agree with earlier results from advanced interferometric synthetic aperture radar (SAR) analysis and field investigations. We investigate four particular slope instabilities, one of which was marked as moderately active, and three as highly active, by earlier field investigations. The resolved along-hill slope displacement is estimated at ~23 mm/year. Our results demonstrate that PolInSAR is an effective method to increase the interferometric coherence and provide improved resolution of deformation features associated with natural hazards.

Full Text Available Nine ERS-1 and ERS-2 descending orbit data acquired over the Aira Caldera between June 1995 and November 1998 were used to create 31 differential interferograms. Although the interferograms exhibit a relatively low level of coherence, even for couples sampling short time intervals (6 months, Differential Interferometric Synthetic Aperture Radar (DinSAR reveals a pattern of range change signal during the observation period in the urban area of Kokubu city. The analysis of the ground deformation time series relative to the earliest ERS images evidenced a maximum uplift of 23 mm between the north and the south of the city during the studied period. Taking the reduced surface of the coherent area into account, we performed a simple modelling of the deformation field assuming a spherical inflating source within an elastic half-space medium. This simple model predicts a source located beneath the centre of Aira Caldera with a maximum volume increase of 30 106 m3 between 1995 and 1997, which would produced an inflation of about 7 cm of the centre of Aira Caldera and 4 cm of the south of Kokubu city. These results are in good agreement with other geophysical observations carried out on Aira caldera during this unrest period. Despite the limited spatial extent of the coherent areas around Aira Caldera, this study shows that DinSAR method using ERS data can be successfully used to detect subtle ground displacement changes of the volcanic complex and thus provides complementary information to ground-based geodetic monitoring of dynamic processes at Aira Caldera and Sakurajima volcano.

This paper presents the results of an investigation on a Deep Seated Gravitational Slope Deformation (DSGSD), previously only hypothesized by some authors, affecting Bisaccia, a small town located in Campania region, Italy. The study was conducted through the integration of conventional methods (geological-geomorphological field survey, air-photo interpretation) and an Advanced-DifferentialInterferometry Synthetic Aperture Radar (A-DInSAR) technique. The DSGSD involves a brittle lithotype (conglomerates of the Ariano Irpino Supersynthem) resting over a Structurally Complex Formation (Varycoloured Clays of Calaggio Formation). At Bisaccia, probably as a consequence of post-cyclic recompression phenomena triggered by reiterated seismic actions, the rigid plate made up of conglomeratic sediments resulted to be split in five portions, showing different rates of displacements, whose deformations are in the order of some centimeter/year, thus inducing severe damage to the urban settlement. A-DInSAR techniques confirmed to be a reliable tool in monitoring slow-moving landslides. In this case 96 ENVIronmental SATellite-Advanced Synthetic Aperture Radar (ENVISAT-ASAR) images, in ascending and descending orbits, have been processed using SUBSOFT software, developed by the Remote Sensing Laboratory (RSLab) group from the Universitat Politècnica de Catalunya (UPC). The DInSAR results, coupled with field survey, supported the analysis of the instability mechanism and confirmed the historical record of the movements already available for the town. - Highlights: • DInSAR confirmed to be a reliable tool in monitoring slow-moving landslides. • Integration with traditional monitoring systems is crucial for DInSAR application. • DInSAR data can be used for the natural risk mitigation related to landslides.

Full Text Available The Sichuan-Tibet grid connection project is a national key project implemented in accordance with the developmental needs of Tibet and the living requirements of 700 thousand local residents. It is the first grid project with special high voltage that passes through eastern margin of the Tibetan Plateau. The ground deformation due to widely distributed landslides and debris flow in this area is the major concern to the safety of the project. The multi-temporal interferometry technique is applied to retrieve the surface deformation information using high resolution X-band SAR imagery. The time series of surface deformation is obtained through the sequential high spatial and temporal resolution TerraSAR images (20 scenes of X-band TerraSAR SLC images acquired from 5 January 2014 to 12 December 2014. The results have been correlated with the permafrost activities and intensive precipitation. They show that the study area is prone to slow to moderate ground motion with the range of −30 to +30 mm/year. Seasonal movement is observed due to the freeze-thaw cycle effect and intensive precipitation weather condition. Typical region analysis suggests that the deformation rate tends to increase dramatically during the late spring and late autumn while slightly during the winter time. The correlations of surface deformations with these two main trigger factors were further discussed. The deformation curves of persistent scatterers in the study area showing the distinct seasonal characteristics coincide well with the effect of freeze-thaw cycle and intensive precipitation. The movement occurring at late spring is dominated by the freeze-thaw cycle which is a common phenomenon in such a high-elevated area as the Tibetan Plateau. Intensive precipitation plays more important role in triggering landsides in the summer season. The combining effect of both factors results in fast slope movement in May. The results also suggest that the movement often occur at

Full Text Available Strike-slip faults may be traced along thousands of kilometers, e.g., the San Andreas Fault (USA or the North Anatolian Fault (Turkey. A closer look at such continental-scale strike faults reveals localized complexities in fault geometry, associated with fault segmentation, secondary faults and a change of related hazards. The North Anatolian Fault displays such complexities nearby the mega city Istanbul, which is a place where earthquake risks are high, but secondary processes are not well understood. In this paper, long-term persistent scatterer interferometry (PSI analysis of synthetic aperture radar (SAR data time series was used to precisely identify the surface deformation pattern associated with the faulting complexity at the prominent bend of the North Anatolian Fault near Istanbul city. We elaborate the relevance of local faulting activity and estimate the fault status (slip rate and locking depth for the first time using satellite SARinterferometry (InSAR technology. The studied NW-SE-oriented fault on land is subject to strike-slip movement at a mean slip rate of ~5.0 mm/year and a shallow locking depth of <1.0 km and thought to be directly interacting with the main fault branch, with important implications for tectonic coupling. Our results provide the first geodetic evidence on the segmentation of a major crustal fault with a structural complexity and associated multi-hazards near the inhabited regions of Istanbul, with similarities also to other major strike-slip faults that display changes in fault traces and mechanisms.

A compensation of atmospheric effects is essential for mm-sensitivity in differential interferometric synthetic aperture radar (DInSAR) techniques. Numerical weather predictions are used to compensate these disturbances allowing a reduction in the number of required radar scenes. Practically, predictions are solutions of partial differential equations which never can be precise due to model or initialisation uncertainties. In order to deal with the chaotic nature of the solutions, ensembles of predictions are computed. From a stochastic point of view, the ensemble mean is the expected prediction, if all ensemble members are equally likely. This corresponds to the typical assumption that all ensemble members are physically correct solutions of the set of partial differential equations. DInSAR allows adding to this knowledge. Observations of refractivity can now be utilised to check the likelihood of a solution and to weight the respective ensemble member to estimate a better expected prediction. The objective of the paper is to show the synergy between ensemble weather predictions and differential interferometric atmospheric correction. We demonstrate a new method first to compensate better for the atmospheric effect in DInSAR and second to estimate an improved numerical weather prediction (NWP) ensemble mean. Practically, a least squares fit of predicted atmospheric effects with respect to a differential interferogram is computed. The coefficients of this fit are interpreted as likelihoods and used as weights for the weighted ensemble mean. Finally, the derived weighted prediction has minimal expected quadratic errors which is a better solution compared to the straightforward best-fitting ensemble member. Furthermore, we propose an extension of the algorithm which avoids the systematic bias caused by deformations. It makes this technique suitable for time series analysis, e.g. persistent scatterer interferometry (PSI). We validate the algorithm using the well known

This paper presents the results of an investigation on a Deep Seated Gravitational Slope Deformation (DSGSD), previously only hypothesized by some authors, affecting Bisaccia, a small town located in Campania region, Italy. The study was conducted through the integration of conventional methods (geological-geomorphological field survey, air-photo interpretation) and an Advanced-DifferentialInterferometry Synthetic Aperture Radar (A-DInSAR) technique. The DSGSD involves a brittle lithotype (conglomerates of the Ariano Irpino Supersynthem) resting over a Structurally Complex Formation (Varycoloured Clays of Calaggio Formation). At Bisaccia, probably as a consequence of post-cyclic recompression phenomena triggered by reiterated seismic actions, the rigid plate made up of conglomeratic sediments resulted to be split in five portions, showing different rates of displacements, whose deformations are in the order of some centimeter/year, thus inducing severe damage to the urban settlement. A-DInSAR techniques confirmed to be a reliable tool in monitoring slow-moving landslides. In this case 96 ENVIronmental SATellite-Advanced Synthetic Aperture Radar (ENVISAT-ASAR) images, in ascending and descending orbits, have been processed using SUBSOFT software, developed by the Remote Sensing Laboratory (RSLab) group from the Universitat Politècnica de Catalunya (UPC). The DInSAR results, coupled with field survey, supported the analysis of the instability mechanism and confirmed the historical record of the movements already available for the town.

Multi-temporal interferometric synthetic aperture radar (InSAR) is an effective tool to detect long-term seismotectonic motions by reducing the atmospheric artifacts, thereby providing more precise deformation signal. The commonly used approaches such as persistent scatterer InSAR (PSInSAR) and small baseline subset (SBAS) algorithms need to resolve the phase ambiguities in interferogram stacks either by searching a predefined solution space or by sparse phase unwrapping methods; however the efficiency and the success of phase unwrapping cannot be guaranteed. We present here an alternative approach - temporarily coherent point (TCP) InSAR (TCPInSAR) - to estimate the long term deformation rate without the need of phase unwrapping. The proposed approach has a series of innovations including TCP identification, TCP network and TCP least squares estimator. We apply the proposed method to the Los Angeles Basin in southern California where structurally active faults are believed capable of generating damaging earthquakes. The analysis is based on 55 interferograms from 32 ERS-1/2 images acquired during Oct. 1995 and Dec. 2000. To evaluate the performance of TCPInSAR on a small set of observations, a test with half of interferometric pairs is also performed. The retrieved TCPInSAR measurements have been validated by a comparison with GPS observations from Southern California Integrated GPS Network. Our result presents a similar deformation pattern as shown in past InSAR studies but with a smaller average standard deviation (4.6. mm) compared with GPS observations, indicating that TCPInSAR is a promising alternative for efficiently mapping ground deformation even from a relatively smaller set of interferograms. ?? 2011.

The PS-InSAR (Persistent Scatterer SARInterferometry) method and precise levelings provide a unique database to detect recent displacements of the Earth's surface. Data of both measurement techniques are analyzed at Geodetic Institute, Karlsruhe Institute of Technology, in order to gain detailed insight into the velocity field of the Upper Rhine Graben (URG). As central and most prominent segment of the European Cenozoic rift system, the seismically and tectonically active Rhine Graben is of steady geo-scientific interest. In the last decades, the URG is characterized by small tectonic movements (geothermal energy) inducing larger surface displacements. To assess the geohazards in the URG area, we aim to provide a map of the current 3D surface displacements with high precision and high spatial resolution. The InSAR and leveling data, and the location of permanent GNSS sites primarily analyzed for the horizontal velocity field, are displayed in Fig. 1. Precise levelings have been carried out by the surveying authorities of Germany, France and Switzerland over the last 100 years building a network of leveling lines. A kinematic network adjustment is applied on the leveling data, providing an accurate solution for vertical displacement rates with accuracies of 0.2 to 0.4 mm/a. The biggest disadvantage of the leveling database is the sparse spatial distribution of the measurement points. Therefore, PS-InSAR is used to significantly increase the number of points within the leveling loops. To obtain a high accuracy for line of sight displacement rates, ERS-1/2 and Envisat data from ascending and descending orbits covering a period from 1992 to 2000 and 2002 to 2010, resp., are processed using StaMPS (Stanford Method for Persistent Scatterers). As the tectonic displacements cover a large area, the separation of atmospheric effects and orbit errors plays an important role in the PS-InSAR processing chain. Besides the tectonic signal, man-induced surface displacements

The addition of interferometric backscattering pairs to the conventional polarimetric synthetic aperture radar (SAR) data over forests and other vegetated areas increases the dimensionality of the data space, in principle enabling the estimation of a larger number of parameters.

The addition of interferometric backscattering pairs to the conventional polarimetric synthetic aperture radar (SAR) data over forests and other vegetated areas increases the dimensionality of the data space, in principle enabling the estimation of a larger number of parameters.

Multiple-aperture SARinterferometry (MAI) has demonstrated outstanding measurement accuracy of along-track displacement when compared to pixel-offset-tracking methods; however, measuring slow-moving (cm/year) surface displacement remains a challenge. Stacking of multi-temporal observations is a potential approach to reducing noise and increasing measurement accuracy, but it is difficult to achieve a significant improvement by applying traditional stacking methods to multi-temporal MAI interferograms. This paper proposes an efficient MAI stacking method, where multi-temporal forward- and backward-looking residual interferograms are individually stacked before the MAI interferogram is generated. We tested the performance of this method using ENVISAT data from Kīlauea Volcano, Hawai‘i, where displacement on the order of several centimeters per year is common. By comparing results from the proposed stacking methods with displacements from GPS data, we documented measurement accuracies of about 1.03 and 1.07 cm/year for the descending and ascending tracks, respectively—an improvement of about a factor of two when compared with that from the conventional stacking approach. Three-dimensional surface-displacement maps can be constructed by combining stacked InSAR and MAI observations, which will contribute to a better understanding of a variety of geological phenomena.

We combine campaign GPS measurements with interferometry synthetic aperture radar (IntSAR) images to map the deformation around and above the Lost Hills oilfield, one of the biggest fields in the USA. GPS at several dozen benchmarks every six months provides a long time series of total vertical and horizontal position change for monuments in the rapidly subsidng ground surface above the oilfield. IntSAR maps using data from the ERS satellites measure relative changes at high spatial resolution with some moderate- to long-wavelength noise sources such as orbit error and atmospheric delays. The GPS data are used to model the moderate to long-wavelength surface deformation field so that the error contributions at those wavelengths in the IntSAR images can be estimated and removed. The rapid subsidence (rates greater than 1 mm/day in 1995) and small size (roughly 3 km wide by 10 km long) require the use of short time intervals for the IntSAR pairs (between 35 days and 8 months), and also processing with the smallest possible sample spacing of 20 by 20 meters to resolve the extreme strain rates. Previously published comparison of the tiltmeter measurements with well fluid extraction demonstrated both an immediate elastoplastic response to depletion and a time-dependent creep response. The high spatial and temporal resolution of the IntSAR measurements will be combined with well records on fluid extraction and injection to separate the delayed response from the immediate reponse to better understand the processes of compaction in the oil reservoir rocks, extremely high-porosity diatomite. This will have direct relevance to the oilfield operations as the compaction can damage the wells and should be minimized. Surprisingly, in some parts of the oilfield, injecting more water to replace the pressure of the oil and gas extracted causes the subsidence rates to increase. Because the fluid input and output at the oilfield is measured, it provides an excellent test bed for

In the Grande da Pipa river basin (north of Lisbon, Portugal), 64% of the landslides inventoried occur on a particular weak rock lithological unit composed by clay and with sandstone intercalations, that is present in 58% of the study (Oliveira et al., 2014). Deep-seated slow moving rotational slides occur essentially on this lithological unit and are responsible for the major damages verified along roads and buildings in the study area. Within this context, landslide hazard assessment, is limited by two major constrains: (i) the slope instability signs may not be sufficiently clear and observable and consequently may not be correctly identifiable through traditional geomorphologic survey techniques and (ii) the non-timely recognition of precursor signs of instability both in landslides activated for the first time and in previously landslide-affected areas (landslide reactivation). To encompass these limitations, the Persistent Scatterer synthetic aperture radar interferometry technique is applied to a data set of 16 TerraSAR-X SAR images, from April of 2010 to March of 2011, available for a small test site of 12.5 square kilometers (Laje-Salema) located on south-central part of the study area. This work's specific objectives are the following: (i) to evaluate the capacity of the Persistent Scatterer displacement maps in assessing landslide susceptibility at the regional scale, and (ii) to assess the capacity of landslide susceptibility maps based on historical landslide inventories to predict the location of actual terrain displacement measured by the Persistent Scatterers technique. Landslide susceptibility was assessed for the test site using the Information Value bivariate statistical method and the susceptibility scores were exported to the Grande da Pipa river basin. The independent validation of the landslide susceptibility maps was made using the historical landslide inventory and the Persistent Scatterer displacement map. Results are compared by computing

Advanced InSAR techniques, for example, Persistent Scatterer Interferometry (PSI), allow long term deformation time series analysis with millimeter accuracy. ESA's Sentinel-1 SAR mission employs the TOPS mode as the standard mode for acquiring InSAR data. It provides a continuous and large coverage at conventional resolution. The idea is to have a wide-area PSI for mapping countries and continents. Although PSI has been successfully demonstrated and validated in the past for various applications, there are some limitations for processing a large-scale dataset. First, PSI is most effective in urban areas which have a large number of stable scatterers. For large-scale PSI, even non-urban areas need to be processed; and this requires robust algorithms for scatterer selection, network construction and inversion, and atmospheric phase removal. Second, the computational load can be very high, due to which, the processing is usually divided into overlapping blocks and merged later. This can however lead to spatial error propagation. This paper presents algorithms which have been developed for a robust PSI reference network estimation, while mitigating error propagation. Instead of dividing the scene into overlapping blocks, a single network (i.e. arcs connecting the scatterers) is created for the full scene. The relative deformation and residual DEM are estimated for the arcs using the LAMBDA estimator. The relative measurements of the network are finally integrated via least-squares inversion. Here, the sparsity of the system of linear equations is exploited to deal with big data (e.g. 10,000,000 arcs for 500,000 scatterers is a typical configuration for Sentinel-1). A QR or LU parallelizable solver is used for fast inversion. Also, variances of the estimates are calculated using a selected parallel inversion method based on LDL decomposition. Demonstration of the algorithms for large-scale deformation monitoring is provided using available Sentinel-1 data for Germany.

Land subsidence is a major worldwide hazard, and its principal causes are subsurface fluid withdrawal, drainage of organic soils, sinkholes, underground mining, hydrocompaction, thawing permafrost, and natural consolidation. Land subsidence causes many problems including: damage to public facilities such as bridges, roads, railroads, electric power lines, underground pipes; damage to private and public buildings; and in some cases of low-lying land, can increase the risk of coastal flooding from storm surges and rising sea-levels. In China, approximately 48600 km2 of land, an area roughly 30 times of the size of the Greater London, has subsided (nearly 50 cities across 16 provinces), and the annual direct economic loss is estimated to be more than RMB 100 million (~12 million). It is believed that the Suzhou-Wuxi-Changzhou region within the Yangtze River Delta is the most severely affected area for subsidence hazards in China. With its global coverage and all-weather imaging capability, Interferometric SAR (InSAR) is revolutionizing our ability to image the Earth's surface and the evolution of its shape over time. In this paper, an advanced InSAR time series technique, InSAR TS + AEM, has been employed to analysed ERS (C-band), Envisat (C-band) and TerraSAR-X (X-band) data collected over the Suzhou-Wuxi-Changzhou region during the period from 1992 to 2013. Validation with precise levelling and GPS data suggest: (1) the accuracy of the InSAR-derived mean velocity measurements is 1-3 mm/yr; (2) InSAR-derived displacements agreed with precise levelling with root mean square errors around 5 mm. It is evident that InSAR TS + AEM can be used to image the evolution of deformation patterns in the Suzhou-Wuxi-Changzhou region over time: the maximum mean velocity decreased from ~12 cm/yr during the period of 1992-1993 to ~2 cm/yr in 2003-2013. This is believed to be a result of the prohibition of groundwater use carried out by Jiangsu provincial government. The combination

Spaceborne Interferometric Synthetic Aperture Radar (InSAR) is a well established technique useful in many land applications, such as landslide monitoring and digital elevation model extraction. One of its major limitation is the atmospheric effect, and in particular the high water vapour spatial and temporal variability which introduces an unknown delay in the signal propagation. However, the sensitivity of SAR interferometric phase to atmospheric conditions could in principle be exploited and InSAR could become in certain conditions a tool to monitor the atmosphere, as it happens with GPS receiver networks. This paper describes a novel attempt to assimilate InSAR derived information on the atmosphere, based on the Permanent Scatterer multipass technique, into a numerical weather forecast model. The methodology is summarised and the very preliminary results regarding the forecast of a precipitation event in Central Italy are analysed. The work was done in the framework of an ESA funded project devoted to the mapping of the water vapour with the aim to mitigate its effect for InSAR applications.

An important application of differentialSARinterferometry (DInSAR) and Persistent Scatterer Interferometry is landslide detection and monitoring. Several studies have been published, which make use of the entire spectrum of SAR data types available in the last 25 years. This paper describes a procedure to update landslide inventory maps using Sentinel-1 data. The paper briefly discusses the main advantages of the Sentinel-1 SAR data. Then it describes the data analysis procedure used to update landslide inventory maps using interferometric data and a number of additional information layers. The effectiveness of the procedure is illustrated by the results of a study area located in the Molise region, in Southern Italy.

We analysed the ground deformation produced by the Mw = 6.1 2014 January 26 and Mw = 6.0 2014 February 3 Cephalonia earthquakes, western Greece. Campaign GPS measurements and RADARSAT-2 synthetic aperture radar (SAR) interferometry provide constraints on the overall deformation produced by the sequence. TerraSAR-X and COSMO-SkyMed SARinterferometry provide constraints on the second earthquake separately. Two permanent GPS stations captured the two coseismic offsets and show no pre- or post-seismic transients. Most of the deformation is concentrated in the Paliki peninsula which is consistent with the location of the seismicity and the damages. Both GPS and SARinterferometry indicate areas with large deformation gradients probably due to shallow effects. Given the limitations on the data and on the knowledge of the structure and rheology of the crust, we used a simple elastic model to fit the ground displacements. Although such model cannot fit all the detail of the deformation, it is expected to provide a robust estimate of the overall geometry and slip of the fault. The good data coverage in azimuth and distance contributes to the robustness of the model. The entire sequence is modelled with a strike slip fault dipping 70° east and cutting most of the brittle crust beneath Paliki, with an upper edge located at 2.5 km depth and a deeper edge at 8.5 km. This fault is oriented N14° which corresponds to the azimuth of the Cephalonia Transform Fault (CTF). The fit to the data is significantly improved by adding a secondary shallow strike-slip fault with low dip angle (30°) with a component of reverse faulting on that shallow fault. The modelling of the February 3 event indicates that the faulting is shallow in the north of Paliki, with a centroid depth of ˜3.2 km. The fit is improved when a single planar fault is replaced by a bent fault dipping ˜30° in the uppermost 2 km and ˜70° below. The fault of the January 26 earthquake, inferred from the difference

Accurate DEMs are required for measuring glacier volume and mass change. The recently launched TanDEM-X (TDX) and TerraSAR-X (TSX) satellite system, which is the first bistatic spaceborne SAR mission, has the potential to acquire the accurate DEMs of most glaciers and ice caps. Here, we report on the application of TSX/TDX data sets for the measurement of mountain glacier DEMs over Tibetan Plateau. A DEM is generated with two pairs of TSX/TDX SAR images obtained in January 2012 over Puruogangri ice field (PIF). Moreover, we also estimate the elevation changes of the PIF by subtracting the SRTM-X DEM from the TSX/TDX DEM. Mean annual thinning rate of -0.0225±0.015 m yr-1 is observed between 2000 and 2012.

Along-track interferometry (ATI) is used to detect ground moving targets against a stationary background in synthetic aperture radar (SAR) imagery. In this paper, we present a novel approach to multi-channel ATI wherein clutter cancellation is applied to each pixel of the multiple SAR images, followed by a Fourier transform to estimate range rate (Doppler). Range rate estimates allow us to compensate for the cross-range offset of the target, thus geo-locating the targets. We then present a number of benefits to this approach.

A digital elevation model (DEM) of the Geikie ice sap in East Greenland has been generated from interferometric C-band synthetic aperture radar (SAR) data acquired with the airborne EMISAR system. GPS surveyed radar reflectors and an airborne laser altimeter supplemented the experiment. The accur......A digital elevation model (DEM) of the Geikie ice sap in East Greenland has been generated from interferometric C-band synthetic aperture radar (SAR) data acquired with the airborne EMISAR system. GPS surveyed radar reflectors and an airborne laser altimeter supplemented the experiment....... The accuracy of the SAR DEM is about 1.5 m. The mean difference between the laser heights and the SAR heights changes from 0 m in the soaked zone to a maximum of 13 m in the percolation zone. This is explained by the fact that the snow in the soaked zone contains liquid water which attenuates the radar signals......, while the transparency of the firn in the percolation zone makes volume scattering dominate at the higher elevations. For the first time, the effective penetration has been measured directly as the difference between the interferometric heights and reference heights obtained with GPS and laser altimetry....

Full Text Available Owing to the development of spaceborne synthetic aperture radar (SAR platforms, and in particular the increase in the availability of multi-source (multi-band and multi-resolution data, it is now feasible to design a surface displacement monitoring application using multi-temporal SARinterferometry (MT-InSAR. Landslides have high socio-economic impacts in many countries because of potential geo-hazards and heavy casualties. In this study, taking into account the merits of ALOS PALSAR (L-band, good coherence preservation and TerraSAR (X-band, high resolution and short revisit times data, we applied an improved small baseline InSAR (SB-InSAR with 3-D phase unwrapping approach, to monitor slope superficial displacement in Hong Kong, China, a mountainous subtropical zone city influenced by over-urbanization and heavy monsoonal rains. Results revealed that the synergistic use of PALSAR and TerraSAR data produces different outcomes in relation to data reliability and spatial-temporal resolution, and hence could be of significant value for a comprehensive understanding and monitoring of unstable slopes.

DifferentialSAR-Interferometry (D-InSAR) is one of the potential source to measure land surface motion induced due to underground coal mining. However, this technique has many limitation such as atmospheric in homogeneities, spatial de-correlation, and temporal decorrelation. Persistent Scatterer Interferometry synthetic aperture radar (PS-InSAR) belongs to a family of time series InSAR technique, which utilizes the properties of some of the stable natural and anthropogenic targets which remain coherent over long time period. In this study PS-InSAR technique has been used to monitor land subsidence over selected location of Jharia Coal field which has been correlated with the ground levelling measurement. This time series deformation observed using PS InSAR helped us to understand the nature of the ground surface deformation due to underground mining activity.

Taiwan is an excellent geomorphic laboratory where both extreme climatic events and high active tectonics compete. Moreover many Earth Sciences and Environmental data bases exist nowadays that help to better constrain both structural geology and active deformations. The latter unfortunately is still poorly known in the Cosatal Range of E.Taiwan in terms of geology due to access difficulties, high relief, paucity of roads, tropical vegetation and high climatic events (typhoons and heavy rainfall) and so on. Indirect methods such as photogrammetric survey using UAV's helps a lot to get high resolution topographic DEM and DTM, better than 10cm in planimetry, that helps a lot to get through careful photo-interpretation, a bird's eye view of the geology. Therefore we were able to much update the famous pre-existing geological maps (Wang and Chen, 1993). Moreover, by combining our high resolution topographic results with those of SARinterferometry (database of Champenois et al, EPSL, 2012), we were able to identify, characterise and quantify the differential active features toward the LOS of the Coastal Range (eastern Taiwan). In order to synthetise and to model the deformation of that famous place, we herein constructed more than 500 parallel projected profiles in order to locate, characterize and quantify the active tectonic features and compare them to the topography and the updated photo-interpreted geology (this work). We then were able to reconstruct the structural geometry of the Coastal Range and the Longitudinal Valley in SE Taiwan. Among our results, we reveal and prove : 1. the whole 2cm differential surrection of the Coastal Range ; 2. the differential displacement between both Central and Coastal Ranges ; 3. we explain the location of the Pinantashi river situated within the Lichi melange that correspond to the maximum surrection of the Coastal Range ; 4. we reveal the different units and their relative displacement within the Coastal Range itself ; 5. we

Full Text Available The complex coherence of polarimetric synthetic aperture radar interferometry (PolInSAR includes the magnitude and phase. The magnitude of coherence is used to measure the quality of the interference phase, and phase center represents the position of the scattering. So, how to improve the accuracy of the coherence magnitude and phase is very important for the forest parameters inversion. Maximum difference of the coherence magnitude or maximum separation of the phase, based on the coherence region, is considered partial information of the complex coherence. In this paper, a new method of coherence optimization, combined with the coherence magnitude and phase information, is established with relational degree. Applied the new approach to estimate the optimal coherence, the optimal polarimetric state of the scattering can be obtained to estimate the optimization coherence. Experimental results show that the optimal coherence criterion, jointed coherence magnitude and phase, can effectively distinguish the phase center of surface scattering and the forest canopy, and improve the reliability of the forest height inversion.

Himalayan and its surroundings distribute the world's largest part of low-latitude high-altitude glaciers and contributed about 10% of total glacier mass lost in recent decade. Remote sensing geodetic observation including satellite altimetry and topography are alternatives of mapping glacier height changes given the harsh environment of in-situ observations. In this research, we applied two pairs of X-band bistatic TerraSAR-X/TanDEM-X images obtained in 2011 and 2012 and formed TanDEM-X DEM with bistatic interferometry. By referring to C and X-band SRTM obtained in 2000. Glacier Mass balance for Everest and its surroundings was -0.446 ± 0.120 m w.e. a-1. Glacier lost at south slope was a bit more severe than north slope, which are -0.481 ± 0.129 m w.e. a-1 and -0.419 ± 0.119 m w.e. a-1. Basically debris-cover suppressed glacier mass lost at most elevations, however for long and large glacier such as Rongbuk, at high elevation debris-cover leaded to a higher lost rate. Comparing to previous study derived glaciers mass balance with stereo photogrammetry, glacier lost rate accelerated in last few decades for the whole Everest region. Two largest glaciers, Rongbuk Glacier at north slope and Khumbu Glacier at south slope both presented increasing mass lost rates.

Full Text Available Digital elevation models (DEMs are essential data sets for disaster risk management and humanitarian relief services as well as many environmental process models. At present, on the hand, globally available DEMs only meet the basic requirements and for many services and modeling studies are not of high enough spatial resolution and lack accuracy in the vertical. On the other hand, LiDAR-DEMs are of very high spatial resolution and great vertical accuracy but acquisition operations can be very costly for spatial scales larger than a couple of hundred square km and also have severe limitations in wetland areas and under cloudy and rainy conditions. The ideal situation would thus be to have a DEM technology that allows larger spatial coverage than LiDAR but without compromising resolution and vertical accuracy and still performing under some adverse weather conditions and at a reasonable cost. In this paper, we present a novel single pass In-SAR technology for airborne vehicles that is cost-effective and can generate DEMs with a vertical error of around 0.3 m for an average spatial resolution of 3 m. To demonstrate this capability, we compare a sample single-pass In-SAR Ka-band DEM of the California Central Valley from the NASA/JPL airborne GLISTIN-A to a high-resolution LiDAR DEM. We also perform a simple sensitivity analysis to floodplain inundation. Based on the findings of our analysis, we argue that this type of technology can and should be used to replace large regions of globally available lower resolution DEMs, particularly in coastal, delta and floodplain areas where a high number of assets, habitats and lives are at risk from natural disasters. We conclude with a discussion on requirements, advantages and caveats in terms of instrument and data processing.

Digital elevation models (DEMs) are essential data sets for disaster risk management and humanitarian relief services as well as many environmental process models. At present, on the hand, globally available DEMs only meet the basic requirements and for many services and modeling studies are not of high enough spatial resolution and lack accuracy in the vertical. On the other hand, LiDAR-DEMs are of very high spatial resolution and great vertical accuracy but acquisition operations can be very costly for spatial scales larger than a couple of hundred square km and also have severe limitations in wetland areas and under cloudy and rainy conditions. The ideal situation would thus be to have a DEM technology that allows larger spatial coverage than LiDAR but without compromising resolution and vertical accuracy and still performing under some adverse weather conditions and at a reasonable cost. In this paper, we present a novel single pass In-SAR technology for airborne vehicles that is cost-effective and can generate DEMs with a vertical error of around 0.3 m for an average spatial resolution of 3 m. To demonstrate this capability, we compare a sample single-pass In-SAR Ka-band DEM of the California Central Valley from the NASA/JPL airborne GLISTIN-A to a high-resolution LiDAR DEM. We also perform a simple sensitivity analysis to floodplain inundation. Based on the findings of our analysis, we argue that this type of technology can and should be used to replace large regions of globally available lower resolution DEMs, particularly in coastal, delta and floodplain areas where a high number of assets, habitats and lives are at risk from natural disasters. We conclude with a discussion on requirements, advantages and caveats in terms of instrument and data processing.

Full Text Available This paper was aimed to analyse the effect of temporal decorrelation in carbon stocks estimation. Estimation of carbon stocks plays important roles particularly to understand the global carbon cycle in the atmosphere regarding with climate change mitigation effort. PolInSAR technique combines the advantages of Polarimetric Synthetic Aperture Radar (PolSAR and Interferometry Synthetic Aperture Radar (InSAR technique, which is evidenced to have significant contribution in radar mapping technology in the last few years. In carbon stocks estimation, PolInSAR provides information about vertical vegetation structure to estimate carbon stocks in the forest layers. Two coherence Synthetic Aperture Radar (SAR images of ALOS PALSAR full-polarimetric with 46 days temporal baseline were used in this research. The study was carried out in Southeast Sulawesi tropical forest. The research method was by comparing three interferometric phase coherence images affected by temporal decorrelation and their impacts on Random Volume over Ground (RvoG model. This research showed that 46 days temporal baseline has a significant impact to estimate tree heights of the forest cover where the accuracy decrease from R2=0.7525 (standard deviation of tree heights is 2.75 meters to R2=0.4435 (standard deviation 4.68 meters and R2=0.3772 (standard deviation 3.15 meters respectively. However, coherence optimisation can provide the best coherence image to produce a good accuracy of carbon stocks.

Noise reduction is one of the most exciting problems in electronic speckle pattern interferometry. We present a homomorphic partial differential equation filtering method for interferometry fringe patterns. The diffusion speed of the equation is determined based on the fringe density. We test the new method on the computer-simulated fringe pattern and experimentally obtain the fringe pattern, and evaluate its filtering performance. The qualitative and quantitative analysis shows that this technique can filter off the additive and multiplicative noise of the fringe patterns effectively, and avoid blurring high-density fringe. It is more capable of improving the quality of fringe patterns than the classical filtering methods.

In this paper, we report on the direct positioning of small multi-directional radar reflectors, so-called octahedrons, with the synthetic aperture radar (SAR) satellite TerraSAR-X. Its highest resolution imaging mode termed staring spotlight enables the use of such octahedron reflectors with a dimension of only half a meter, but still providing backscatter equivalent to 1-2 cm observation error. Four octahedrons were deployed at Wettzell geodetic observatory, and observed by TerraSAR-X with 12 acquisitions in three different geometries. By applying our least squares stereo SAR algorithm already tested with common trihedral corner reflectors (CRs), and introducing a novel differential extension using one octahedron as reference point, the coordinates of the remaining octahedrons were directly retrieved in the International Terrestrial Reference Frame (ITRF). Contrary to our standard processing, the differential approach does not require external corrections for the atmospheric path delays and the geodynamic displacements, rendering it particularly useful for joint geodetic networks employing SAR and GNSS. In this paper, we present and discuss both methods based on results when applying them to the aforementioned Wettzell data set of the octahedrons. The comparison with the independently determined reference coordinates confirms the positioning accuracy with 2-5 cm for the standard approach, and 2-3 cm for the differential processing. Moreover, we present statistical uncertainty estimates of the observations and the positioning solutions, which are additionally provided by our parameter estimation algorithms. The results also include our 1.5 m CR available at Wettzell, and the outcomes clearly demonstrate the advantage of the multi-directional octahedrons over conventional CRs for global positioning applications with SAR.

Full Text Available From leveling to SAR-based interferometry, the monitoring of land subsidence in coastal transitional environments significantly improved. However, the simultaneous assessment of the ground movements in these peculiar environments is still challenging. This is due to the presence of relatively small built-up zones and infrastructures, e.g., coastal infrastructures, bridges, and river embankments, within large natural or rural lands, e.g., river deltas, lagoons, and farmland. In this paper we present a multi-band SAR methodology to integrate COSMO-SkyMed and ALOS-PALSAR images. The method consists of a proper combination of the very high-resolution X-band Persistent Scatterer Interferometry (PSI, which achieves high-density and precise measurements on single structures and constructed areas, with L-band Short-Baseline SARInterferometry (SBAS, properly implemented to raise its effectiveness in retrieving information in vegetated and wet zones. The combined methodology is applied on the Po River Delta and Venice coastland, Northern Italy, using 16 ALOS-PALSAR and 31 COSMO-SkyMed images covering the period between 2007 and 2011. After a proper calibration of the single PSI and SBAS solution using available GPS records, the datasets have been combined at both the regional and local scales. The measured displacements range from ~0 mm/yr down to −35 mm/yr. The results reveal the variable pattern of the subsidence characterizing the more natural and rural environments without losing the accuracy in quantifying the sinking of urban areas and infrastructures. Moreover, they allow improving the interpretation of the natural and anthropogenic processes responsible for the ongoing subsidence.

Two altimetry models extracting DEM (Digital Elevation Model) with the GBSAR (Ground-Based Synthetic Aperture Radar) technology are studied and their accuracies are analyzed in detail. The approximate and improved altimetry models of GBSAR were derived from the spaceborne radar altimetry based on the principles of the GBSAR technology. The error caused by the parallel ray approximation in the approximate model was analyzed quantitatively, and the results show that the errors cannot be ignored for the ground-based radar system. For the improved altimetry model, the elevation error expression can be acquired by simulating and analyzing the error propagation coefficients of baseline length, wavelength, differential phase and range distance in the mathematical model. By analyzing the elevation error with the baseline and range distance, the results show that the improved altimetry model is suitable for high-precision DEM and the accuracy can be improved by adjusting baseline and shortening slant distance.

Pyroclastic flows from the 1990-1995 eruption of Unzen, a dacitic volcano in the southwest of Japan, descended the mountain along a variety of routes causing widespread damage and loss of life. Interferograms constructed from JERS-1 L-band Synthetic Aperture Radar (SAR) images show a number of features related to these pyroclastic flows and their secondary effects. The most useful interferogram in this respect is based on images acquired on 22 July 1993 and 1 December 1993 and shows the descent paths for pyroclastic flows occurring in four valley systems within this time window as zones of decorrelation caused by the repeated resurfacing. The 22 July 1993 SAR image was, through considerable good fortune, acquired only 2.6 days after a major pyroclastic flow had descended into the Mizunashi valley so that, in the absence of rainfall, the fresh 2-m-thick deposits were dry when first imaged. The largest differential surface height changes observed in the interferogram represent height decreases in the vertical of ˜12 cm and, significantly, lie within a small region of the Mizunashi valley which was resurfaced by the pyroclastic flow of 19 July 1993 but not subsequently. Within this small region, radar coherence is higher (maximum correlation value of ˜0.75) in a center-valley site where ash but relatively few large boulders are present. In a qualitative sense, the new ash surfaces exhibit higher levels of radar coherence than the older (pre-19 July) deposits. In other Unzen valleys visited by pyroclastic flows, smaller differential surface height decreases (˜4 cm) are observed where the surface deposits were emplaced by events taking place between 1-3 months before the acquisition date of the 22 July 1993 image. The 'extra' ˜8 cm of surface height decrease observed in the case of the freshly laid Mizunashi deposits must result from a deflationary mechanism (or mechanisms) operating in a spatially uniform manner in order for radar coherence to be maintained. A

Full Text Available Persistent Scatterer interferometry (PSI represents a powerful tool for the detection and monitoring of tiny surface deformations in vast areas, allowing a better understanding of its triggering mechanisms, planning of mitigation measures, as well as to find better solutions for social and environmental issues. However, there is no record hitherto of its use in active open pit mine in tropical rainforest environment. In this paper we evaluate the use of the PSI technique for the detection and monitoring of mine slope deformations in the N4W iron mine and its surroundings, Pará State, Northern Brazil. The PSI processing was performed with 18 ascending SAR scenes of the TerraSAR-X satellite acquired in the dry season of 2012. The results showed a significant number of widely distributed persistent scatterers. It was observed that most of the study area was stable during the time span. Nevertheless, high deformation rates (312 mm/year were mapped over the mine waste piles, but do not offer any hazard, since they are expected displacements of meters in magnitude for these manmade land structures. Additionally, it was mapped tiny deformation rates in both the east and west flanks of pits 1 and 2. The main underlying reasons can be assigned to the accommodation phenomena of very poor rock masses, to the local geometric variations of the slope cuts, to the geological contact between ironstones and the country rocks, to the exploitation activities, as well as to the major geological structures. This study showed the applicability of the PSI technique using TerraSAR-X scenes in active open pit mines in tropical moist environment. However, the PSI technique is not capable in providing real-time warnings, and faces limitations due to SAR viewing geometry. In this sense, we strongly recommend the use of radar scenes acquired in both ascending and descending orbits, which would also provide a more complete understanding of the deformation patterns.

International audience; This paper describes the residual movements associated with deep coalmines (France). The Nord-Pas-de Calais basin has been monitored since 10 years by traditional method. The interferometry technics are applied on Nord-Pas-de-Calais coal basin. In this study, both differentialSARInterferometry (DINSAR) and Persistent Scaterrers Interferometry (PSI) are used to estimate the induced deformations during 12 years (1992 to 2004) after the end of exploitation. 88 images of...

In this paper, we first present the general description for partial differential equations (PDEs) based image processing methods, including the basic idea, the main advantages and disadvantages, a few representative PDE models, and the derivation of PDE models. Then we review our contributions on PDE-based anisotropic filtering methods for electronic speckle pattern interferometry, including the second-order, fourth-order, and coupled nonoriented PDE filtering models and the second-order and coupled nonlinear oriented PDE filtering models. We have summarized the features of each model.

The principles and applications of laser real-time holographic interferometry (LRTHI) and radar differentialinterferometry (RDI) technologies are described in this paper, respectively. By using LRTHI, we can observe the deformation of samples under pressure in the lab and study the anomaly characteristics relating to different strain fields in different fracture-developing areas; while by using RDI, we can observe the landform and surface deformation. The results of deformation observed before and after the Ms=7.9 Mani earthquake (Tibet) and Ms=6.2Shangyi-Zhangbei earthquake in China are obtained. It is pointed out that LRTHI and RDI are similar, which study the characteristics of anomalous deformation field by fringe variations for both of them. Therefore, the observation of deformation field in the seismogenic process, especially in the period impending an earthquake by RDI, and the comparative study in the lab by LRTHI are of great significance.

The principles and applications of laser real-time holographic interferometry (LRTHI) and radar differentialinterferometry (RDI) technologies are described in this paper, respectively. By using LRTHI, we can observe the deformation of samples under pressure in the lab and study the anomaly characteristics relating to different strain fields in different fracture-developing areas; while by using RDI, we can observe the landform and surface deformation. The results of deformation observed before and after the M S=7.9 Mani earthquake (Tibet) and M S=6.2 Shangyi-Zhangbei earthquake in China are obtained. It is pointed out that LRTHI and RDI are similar, which study the characteristics of anomalous deformation field by fringe variations for both of them. Therefore, the observation of deformation field in the seismogenic process, especially in the period impending an earthquake by RDI, and the comparative study in the lab by LRTHI are of great significance.

Unveiling the structure of the Broad Line Region (BLR) of AGNs is critical to understand the quasar phenomenon. Resolving a few BLRs by optical interferometry will bring decisive information to confront, complement and calibrate the reverberation mapping technique, basis of the mass-luminosity relation in quasars. BLRs are much smaller than the angular resolution of the VLT and Keck interferometers and they can be resolved only by differentialinterferometry very accurate measurements of differential visibility and phase as a function of wavelength. The latter yields the photocenter variation with wavelength, and constrains the size, position and velocity law of various regions of the BLR. AGNs are below the magnitude limit for spectrally resolved interferometry set by currently available fringe trackers. A new "blind" observation method and a data processing based on the accumulation of 2D Fourier power and cross spectra permitted us to obtain the first spectrally resolved interferometric observation of a BL...

极化干涉SAR树高反演是当前SAR研究领域的一个重要方向。相干最优化是在各种散射机制中寻求最优的散射机制，对于极化干涉SAR，它不仅可以改善不同极化通道之间的相干系数，还能改善地物分类和垂直结构参数估计。首先详细分析极化干涉SAR反演树高的相干最优化理论基础，然后利用仿真数据从不同极化通道对线极化、Pauli基极化和最优极化进行了试验，从定性和定量进行对比分析，研究结果进一步验证相干最优分解方法可以提高干涉相干系数，并获得更好的干涉图，从而有利于提高树高反演的精度。%Tree height inversion based on polarization interference SAR is an important direction in the current SAR research field .By searching for the optimal mechanism in various scattering mechanisms , for POL-InSAR system, it not only can be used to improve the coherence between different polarization channels , but also can help to improve classification and vertical structure parameters esti -mation process .The optimal mechanism of tree height inversion based on polarization interference SAR was elaborated and analyzed , and an experiment on the simulation data of line polarization , Pauli Base change and the optimal polarization was done .By making a contrastive analysis on aspects of qualitative and quantitative information , we confirmed that coherent optimal decomposition method can increase interference coherent coefficient and help us get better interferogram so as to improve tree height inversion ′s precision.

Although water vapor disturbance has been long term recognized as the major error source in differential Interferometric Synthetic Aperture Radar (d-InSAR) techniques for the ground deformation monitoring and topography reconstruction, it provides opportunities to extract the atmospheric water-vapor information from satellite SAR imageries that can be further used to support studies on earth energy budget, climate, the hydrological cycle, and meteorological forecasting, etc. The water vapor contribution in interferometric phases is normally referred as the atmospheric delay dominated by water vapor rather than condensed water (e.g. cloud). D-InSAR can produce maps of the column water vapor amounts (equivalent to integrated water vapor (IWV) or Precipitable Water Vapor (PWV) in other literatures) that are important parameters quantitatively describe the total amount of water vapor overlying a point on the earth surface. Similar products have been operationally produced in multi-spectrum remote sensing, e.g. Moderate-resolution Imaging Spectroradiometer (MODIS) with a spatial resolution in 500 m to 1km; Whereas, the PWV products derived by d-InSAR have remarkably high spatial resolution that can capture fine scale of water vapor variations in space as small as tens of meters or even less. In recent years, some efforts have been made to derive the water vapor products from interferogram and analyze the corresponding products quality, such as studies comparing integrated water vapor derived from interferometric phases to other measurements (e.g. MERIS, MODIS, GNSS), studies on deriving absolute water vapor products from d-InSAR, and studies on integrating d-InSAR water vapor products in meteorological numerical forecast. In this study, considering these limitation factors and based on previous studies, we discuss the accuracy and statistics of the water vapor products from satellite SAR, including (1) Accuracy of the differential water vapor products; (2) Sources of

Full Text Available Spatiotemporal deformation of existing sinkholes and the surrounding region in Wink, TX are probed using time-series interferometric synthetic aperture radar (InSAR methods with radar images acquired from the Sentinel-1A satellite launched in April 2014. The two-dimensional deformation maps, calculated using InSAR observations from ascending and descending tracks, reveal that much of the observed deformation is vertical. Our results indicate that the sinkholes are still influenced by ground depression, implying that the sinkholes continue to expand. Particularly, a region 1 km northeast of sinkhole #2 is sinking at a rate of up to 13 cm/year, and its aerial extent has been enlarged in the past eight years when compared with a previous survey. Furthermore, there is a high correlation between groundwater level and surficial subsidence during the summer months, representing the complicated characteristics of sinkhole deformation under the influence of successive roof failures in underlying cavities. We also modeled the sinkhole deformation in a homogenous elastic half-space with two dislocation sources, and the ground depression above cavities could be numerically analyzed. Measurements of ongoing deformation in sinkholes and assessments of the stability of the land surface at sinkhole-prone locations in near real-time, are essential for mitigating the threat posed to people and property by the materialization of sinkholes.

Hanoi was the capital of 12 Vietnamese dynasties, where the most historical relics, archaeological ruins and ancient monuments are located over Vietnam. However, those heritage assets are threatened by the land subsidence process occurred in recent decades, which mainly triggered by massive groundwater exploitation and construction activities. In this work, we use a set of high resolution TerraSAR-X images to map small-scale land subsidence patterns in the Historical Centre of Hanoi from April 2012 to November 2013. Images oversampling is integrated into the Small Baseline InSAR processing chain in order to enlarge the monitoring coverage by increasing the point-wise measurements, maintaining the monitoring scale of single building and monument. We analyzed over 2.4 million radar targets on 13.9 km2 area of interest based on 2 main sites: The Citadel, the Old Quarter and French Quarter. The highest subsidence rate recorded is -14.2 mm/year. Most of the heritage assets are considered as stable except the Roman Catholic Archdiocese and the Ceramic Mosaic Mural with the subsidence rates are -14.2 and -13.7 mm/year, respectively. Eventually, optical image and soil properties map are used to determine the causes of subsidence patterns. The result shows the strong relationships between the existing construction sites, the component of sediments and land subsidence processes that occurred in the study site.

Persistent Scatterer Interferometry (PSInSAR) is a new method of interferometric processing that overcomes the limitations of conventional Synthetic Aperture Radar differentialinterferometry (DInSAR) and is capable of detecting millimeter scale ground displacements. PSInSAR eliminate anomalies due to atmospheric delays and temporal and geometric decorrelation eminent in tropical regions by exploiting the temporal and spatial characteristics of radar interferometric signatures derived from time-coherent point-wise targets. In this study, PSInSAR conducted in Mayon Volcano, Albay Province, Bicol, Philippines, reveal tectonic deformation passing underneath the volcano. Using 47 combined ERS and ENVISAT ascending and descending imageries, differential movement between the northern horst and graben on which Mayon volcano lies, is as much as 2.5 cm/year in terms of the line-of-sight (LOS) change in the radar signal. The northern horst moves in the northwest direction whereas the graben moves mostly downward. PSInSAR results when coupled with morphological interpretation suggest left-lateral oblique-slip movement of the northern bounding fault of the Oas graben. The PSInSAR results are validated with dGPS measurements. This work presents the functionality of PSInSAR in a humid tropical environment and highlights the probable landslide hazards associated with an oversteepened volcano that may have been further deformed by tectonic activity.

Full Text Available While the use of differential TomoSAR based on compressive sensing (CS makes it possible to solve the layover problem and reconstruct the deformation information of an observed urban area scene acquired by moderate-high resolution SAR satellite, the performance of the reconstruction decreases for a sparse and structural observed scene due to ignoring the structural characteristics of the observed scene. To deal with this issue, the method for differentialSAR tomography based on Khatri-Rao subspace and block compressive sensing (KRS-BCS is proposed. The proposed method changes the reconstruction of the sparse and structural observed scene into a BCS problem under Khatri-Rao subspace, using the structure information of the observed scene and Khatri-Rao product property of the reconstructed observation matrix for differential TomoSAR, such that the KRS-BCS problem is efficiently solved with a block sparse l1/l2 norm optimization signal model, and the performance of resolution capability and reconstruction estimation is compared and analyzed qualitatively and quantitatively by the theoretical analysis and the simulation experiments, all of the results show the propose KRS-BCS method practicably overcomes the problems of CS method, as well as, quite maintains the high resolution characteristics, effectively reduces the probability of false scattering target and greatly improves the reconstruction accurate of scattering point. Finally, the application is taking the urban area of the Mobara(in Chiba, Japan as the test area and using 34 ENVISAT-ASAR images, the accuracy is verifying with the reference deformations derived from first level point data and GPS tracking data, the results show the trend is consistent and the overall deviation is small between reconstruction deformations of the propose KRS-BCS method and the reference deformations, and the accuracy is high in the estimation of the urban area deformation.

We constructed and analyzed the ground surface displacement associated with the 2016 Kumamoto earthquake sequence using satellite radar interferometry images of the Advanced Land Observing Satellite 2. The radar interferogram generally shows elastic deformation caused by the main earthquakes, but many other linear discontinuities showing displacement are also found. Approximately 230 lineaments are identified, some of which coincide with the positions of known active faults, such as the main earthquake faults belonging to the Futagawa and Hinagu fault zones and other minor faults; however, there are much fewer known active faults than lineaments. In each area, the lineaments have a similar direction and displacement to each other; therefore, they can be divided into several groups based on location and major features. Since the direction of the lineaments coincides with that of known active faults or their conjugate faults, the cause of the lineaments must be related to the tectonic stress field of this region. The lineaments are classified into the following two categories: (1) main earthquake faults and their branched subfaults and (2) secondary faults that are not directly related to the main earthquake but whose slip was probably triggered by the main earthquake or aftershocks.[Figure not available: see fulltext.

This paper discusses several aspects of theories on SARinterferometry. The differentmathematic models of interferometry have been discussed and analysed. The paper points out thatthe ground coordinate system should bechosen carefully in case of using the mathematic modelsuggested by C. Prati et al and the tangent plane coordinate system must be taken into account.The model proposed by Ph. Hartl et al can be used without considering the earth curveture, butthe calculations of base line and the incident angle for every point are the key factors and difficultto be done. The model by R. Gens et al is different in the conception of phase difference which isfor one point only, not the difference of phase difference of two neighboring points. The paper aslopoints out that the problems mentioned above should be taken into the consideration for applica-tions. A mathematic model for elevation calculation has been proposed based upon the phase differ-ence of two neighbor points to same antenna, and precise control point as the “seed”, without tak-ing into account the base-line assessment. The adjustments for the image coordinates of controlpoints and satellite position parameters according to the imaging equations have also been suggested in order to meet the needs of the precision of control points and satellite position for phase unwrapping and elevation calculation,as well as the method of base-line assessment.%就雷达影像干涉测量的若干理论问题进行了讨论，提出了一种高程解算数学模型，该模型基于相邻两点对于同一天线的相位差，以精确可靠的控制点为出发点，可以不必顾及基线估计；提出了将控制点影像坐标与卫星位置参量按成像方程进行平差，以保证相位解缠和高程解算对控制点和卫星位置精度的要求，指出了在此基础上的基线估计方法。

This paper presents a new algorithm to generate the interferometry fringe with high quality in real-time. It utilizes the techniques of down-sampling and interferometry multi-look processing, the look-up table with linear interpolation, the ECS auto-registration imaging algorithm with non-linear approximation,the real-time interferometry motion compensation,and the improved fast algorithm of computing coherence and filtering the interferometry fringe. The feasibility of generating the interferometry fringe in real-time with hardware is 8nalyzed and the structure of hardware is given to realize the algorithm too. In the end,the interferometry fringe and coherence map are generated by the algorithm for the airborne X-band InSAR dato of Institute of Electronics, Chinese Academy of Sciences,and the results prove the validity of the algorithm.%为了能实时产生高质量的干涉条纹提出了一种新算法.算法采用了降采样与干涉多视处理相结合的技术、线性插值查表法、非线性近似的ECS自配准成像算法、实时干涉运补、相干系数快速计算以及快速干涉滤波方法,并对该算法实时产生干涉条纹的可行性进行了分析,给出了实现该算法的硬件结构.最后针对电子所X波段机载双天线InSAR数据,利用该算法产生了干步条纹和相干系数图,证明了算法的有效性.

Images derived from repeat-pass spaceborne interferometric synthetic aperture radar (InSAR) systems offer the possibility of mapping surface deformation of small spatial extent and monitoring its spatio-temporal evolution. A slow local subsidence has been detected at the Cerro Prieto geothermal field from images acquired by the European Space Agency remote sensing satellites ERS-1/2 between 1993 and 1997. Although agricultural activity in the area limited the investigation, interferometric monitoring revealed that the ground deformation is associated with the withdrawal of geothermal fluid and agreed with the leveling data. Modeling of the subsidence was carried out assuming elastic deformation in a half-space from simple point sources, of which five were necessary to reproduce the fringe patterns observed on the interferograms. The depths and locations of three of the sources are compatible with the location of the known reservoir. The study improves prior knowledge of the displacement field and of the mecanisms involved in the subsidence phenomenon.

The optical surface profiler offers fast non-contact and high-precision 3D metrology for complex surface features, which are widely used in the field of precision machining manufacturing. The optical surface profiler traditionally adopts the white light interference (WLI) technique which mainly includes optical interference system and high-precision displacement stage. The accuracy of the displacement table determines the longitudinal resolution of the instrument. In this paper, a novel WLI technique is proposed, i.e. full-field heterodyne WLI, which combines common displacement stage, low differential-frequency heterodyne system and optical interferometry system. The low differential-frequency heterodyne system generates heterodyne signal in the range of laser coherence length. By using the digital phase shift in substitution for the mechanical phase shift, the vertical resolution increases from the sub-nanometer level to the sub-angstrom level. Due to the low difference frequency technique, the common area array detector acquisition is available. A fixed displacement stage position obtains a set of three-dimensional data cubes. Through Fourier-Transform process of the time series data, the initial phase of each pixel at a specific heterodyne frequency is calculated and transformed into surface height information. By using phase unwrapping, the object surface profile can be restored within the laser coherence length. Through digital phase-shifting, phase extraction technology replaces the intensity extraction technology, the moving distance of the displacement can be calibrated with high precision. Thus it can achieve a large range of high-precision contour measurement and reduce the cost of the instrument.

Satellite radar interferometry (InSAR) is a precise and efficient technique to monitor deformation on Earth with millimeter precision. Most InSAR applications focus on geophysical phenomena, such as earthquakes, volcanoes, or subsidence. Monitoring civil infrastructure with InSAR is relatively new,

In ground engineering the need for deformation measurements is urgent. SARinterferometry can be used to measure small (sub-wavelength) deformations. An experiment to investigate this for dike deformations was set up, using the C-band SAR system PHARUS (PHased ARray Universal SAR). This paper descri

ii ) mitigating against common “Radio Frequency Interference (RFI)” and intentional “Directive Jamming of Airborne & Space borne POL-IN-SAR Imaging...modal SAR Imaging platforms that support both systems – such as the NASA-JPL AIR/TOP-SAR [106, 121, 122], the DLR E-SAR [223], the ONERA RAMSES SAR...about 35 dB) with calibration sensitivity of 0.1 dB in amplitude and 1º in polarimetric phase; must possess a very high dynamic range; ( ii ) they must

Are there any earthquakes in Australia? Although most Australians are not as familiar with earthquakes as citizens in countries such as Japan, there are some quakes on the Australian continent every year. Differential Synthetic Aperture Radar Interferometry (DInSAR) has been widely used in recent years for monitoring crustal deformation due to earthquakes, volcanoes, underground mining, oil extraction,and so on. Hence the follow-on question is, can repeat-pass satellite DInSAR be used in Australian regions to monitor earthquakes? Nine ERS-1 and ERS-2 radar images of the Burakin region in Western Australia were used to form the InSAR pairs.Twenty-two InSAR pairs were formed and were used to study the temporal decorrelation characteristics in the Burakin area. It was found that good coherence could be maintained all over the full scene for a pair spanning 211 d. The repeat cycles of RADARSAT and ERS (all C-band SAR missions) are 24 and 35 drespectively, Furthermore it is easier to maintain good coherence in L-band SAR images (e.g. the JERS-1 mission has a 44 d repeat cycle). Therefore the authors are confident that repeat-pass differential InSAR can be used to monitor ground deformation due to earthquakes in the Burakin region.

Full Text Available The pathogenesis of severe acute respiratory syndrome coronavirus (SARS-CoV is likely mediated by disproportional immune responses and the ability of the virus to circumvent innate immunity. Using functional genomics, we analyzed early host responses to SARS-CoV infection in the lungs of adolescent cynomolgus macaques (Macaca fascicularis that show lung pathology similar to that observed in human adults with SARS. Analysis of gene signatures revealed induction of a strong innate immune response characterized by the stimulation of various cytokine and chemokine genes, including interleukin (IL-6, IL-8, and IP-10, which corresponds to the host response seen in acute respiratory distress syndrome. As opposed to many in vitro experiments, SARS-CoV induced a wide range of type I interferons (IFNs and nuclear translocation of phosphorylated signal transducer and activator of transcription 1 in the lungs of macaques. Using immunohistochemistry, we revealed that these antiviral signaling pathways were differentially regulated in distinctive subsets of cells. Our studies emphasize that the induction of early IFN signaling may be critical to confer protection against SARS-CoV infection and highlight the strength of combining functional genomics with immunohistochemistry to further unravel the pathogenesis of SARS.

The paper gives an overview of the principle and application of generating DEM from SAR, including the principle and processing flow of generating DEM from single SAR and SARinterferometry. Afterwards, the application fields of InSAR for terrain surveying, volcanic terrain surveying and D-InSAR for monitoring ground subsiding are listed and described as well.The problem and prospect of application are also pointed out in the last part of this paper.

The DifferentialSARInterferometry (DInSAR) is one of the most powerful devices for monitoring deformation processes on the Earth surface. Here, a dataset of TerraSAR-X StripMap imagery covering almost the whole Crotone province territory, located in the south of the Italian peninsula, has been selected and processed. The time span goes from April 2008 to June 2010. In this work, two different multitemporal interferometry (MTI) approaches and two different software packages have been used and compared in order to identify benefits/constraints of each MTI approach and each software. Such approaches are: the ‘permanent’ (or ‘persistent’, or ‘point-like’) scatterers [1] implemented on the SARscape® software [2], and the Temporal Sublook Spectral Coherence (TSSC), derived from Coherent Pixel Technique algorithm and works on SUBSOFT processor, developed by the Remote Sensing Laboratory (RSLab) group, from the Universitat Politècnica de Catalunya (UPC) [3-5].

On 19 March 2008, a small explosive eruption at the summit of Kīlauea Volcano, Hawai‘i, heralded the formation of a new vent along the east wall of Halema‘uma‘u Crater. In the ensuing years, the vent widened due to collapses of the unstable rim and conduit wall; some collapses impacted an actively circulating lava pond and resulted in small explosive events. We used synthetic aperture radar data collected by the TerraSAR-X satellite, a joint venture between the German Aerospace Center (DLR) and EADS Astrium, to identify and analyze small-scale surface deformation around the new vent during 2008-2012. Lidar data were used to construct a digital elevation model to correct for topographic phase, allowing us to generate differential interferograms with a spatial resolution of about 3 m in Kīlauea's summit area. These interferograms reveal subsidence within about 100 m of the rim of the vent. Small baseline subset time series analysis suggests that the subsidence rate is not constant and, over time, may provide an indication of vent stability and potential for rim and wall collapse -- information with obvious hazard implications. The deformation is not currently detectable by other space- or ground-based techniques.

We extend and refine previous work [Appl. Opt. 46, 2907 (2007)]. Combining the coupled nonlinear partial differential equations (PDEs) denoising model with the ordinary differential equations enhancement method, we propose the new denoising and enhancing model for electronic speckle pattern interferometry (ESPI) fringe patterns. Meanwhile, we propose the backpropagation neural networks (BPNN) method to obtain unwrapped phase values based on a skeleton map instead of traditional interpolations. We test the introduced methods on the computer-simulated speckle ESPI fringe patterns and experimentally obtained fringe pattern, respectively. The experimental results show that the coupled nonlinear PDEs denoising model is capable of effectively removing noise, and the unwrapped phase values obtained by the BPNN method are much more accurate than those obtained by the well-known traditional interpolation. In addition, the accuracy of the BPNN method is adjustable by changing the parameters of networks such as the number of neurons.

The ordinary differential equation (ODE) and partial differential equation (PDE) image- processing methods have been applied to reduce noise and enhance the contrast of electronic speckle pattern interferometry fringe patterns. We evaluate the performance of a few representative PDE denoising models quantitatively with two parameters called image fidelity and speckle index, and then we choose a good denoising model. Combining this denoising model with the ODE enhancement method, we make it possible to perform contrast enhancement and denoising simultaneously. Second, we introduce the delta-mollification method to smooth the unwrapped phase map. Finally, based on PDE image processing, delta mollification and some traditional techniques, an approach of phase extraction from a single fringe pattern is tested for computer-simulated and experimentally obtained fringe patterns. The method works well under a high noise level and limited visibility and can extract accurate phase values.

The ordinary differential equation (ODE) and partial differential equation (PDE) image- processing methods have been applied to reduce noise and enhance the contrast of electronic speckle pattern interferometry fringe patterns. We evaluate the performance of a few representative PDE denoising models quantitatively with two parameters called image fidelity and speckle index, and then we choose a good denoising model. Combining this denoising model with the ODE enhancement method, we make it possible to perform contrast enhancement and denoising simultaneously. Second, we introduce the δ-mollification method to smooth the unwrapped phase map. Finally, based on PDE image processing, δ mollification and some traditional techniques, an approach of phase extraction from a single fringe pattern is tested for computer-simulated and experimentally obtained fringe patterns. The method works well under a high noise level and limited visibility and can extract accurate phase values.

A non-invasive method of detecting glucose concentration using differential absorption low-coherence interferometry (DALCI) based on rapid scanning optical delay line is presented. Two light sources, one centered within (1625 nm) a glucose absorption band, while the other outside (1310 nm) the glucose absorption band, are used in the experiment. The low-coherence interferometry (LCI) is employed to obtain the signals back-reflecting from the iris which carries the messages of material concentration in anterior chamber. Using rapid scanning optical delay line (RSOD) as the reference arm, we can detect the signals in a very short time. Therefore the glucose concentration can be monitored in real-time, which is very important for the detection in vivo. In our experiments, the cornea and aqueous humor can be treated as nearly non-scattering substance. The difference in the absorption coefficient is much larger than the difference in the scattering coefficient, so the influence of scattering can be neglected. By subtracting the algorithmic low-coherence interference signals of the two wavelengths, the absorption coefficient can be calculated which is proportional to glucose concentration. To reduce the speckle noise, a 30 variation of signals were used before the final calculation of the glucose concentration. The improvements of our experiment are also discussed in the article. The method has a potential application for noninvasive detection of glucose concentration in vivo and in real-time.

Full Text Available Abstract Background SARS coronavirus (SARS-CoV was identified as the etiological agent of SARS, and extensive investigations indicated that it originated from an animal source (probably bats and was recently introduced into the human population via wildlife animals from wet markets in southern China. Previous studies revealed that the spike (S protein of SARS had experienced adaptive evolution, but whether other functional proteins of SARS have undergone adaptive evolution is not known. Results We employed several methods to investigate selective pressure among different SARS-CoV groups representing different epidemic periods and hosts. Our results suggest that most functional proteins of SARS-CoV have experienced a stepwise adaptive evolutionary pathway. Similar to previous studies, the spike protein underwent strong positive selection in the early and middle phases, and became stabilized in the late phase. In addition, the replicase experienced positive selection only in human patients, whereas assembly proteins experienced positive selection mainly in the middle and late phases. No positive selection was found in any proteins of bat SARS-like-CoV. Furthermore, specific amino acid sites that may be the targets of positive selection in each group are identified. Conclusion This extensive evolutionary analysis revealed the stepwise evolution of different functional proteins of SARS-CoVs at different epidemic stages and different hosts. These results support the hypothesis that SARS-CoV originated from bats and that the spill over into civets and humans were more recent events.

As the largest water conservation project in China, the Three Gorges Reservoir has attracted a lot of attention. However, the rise in water level due to the dam operation has caused many ecological problems. Since the impoundment of the Three Gorges Reservoir in the year 2003, many landslides have taken place. The Shuping landslide is a reactivated landslide and has been continuously moving since the impoundment. It has resulted in serious dangers to local residence and the role of the Yangtze River as an inland waterway. Spaceborne Synthetic Aperture Radar (SAR) sensors obtain images periodically and regionally, from which the characteristics of the slope movement could be obtained timely and cost effectively. In this study, an adapted time series InSAR technique considering SRTM bias is proposed and used to process TerraSAR-X strip map images with 3 meters resolution which collected in the first quarter of 2012. Compared with previous studies with low resolution SAR data, our results obtain much more stable points and reveal the movement pattern of the active slope of Shuping landslide in detail, and they show that there are two main landslide bodies obviously; one is located in the eastern part of the landslide, while the other is located in the western part of the landslide, the movement velocity is up to 40 mm month-1, and the results are well-consistent with the in situ results. Furthermore the active movement boundaries was identified through analysing the time series InSAR results, the shape of the landslide is chair-like, and the boundaries lie mostly along ditches. The results show that more details about the landslide could be revealed using the proposed time series InSAR method and high resolution TerraSAR-X SAR data, and this provide a more comprehensive way for landslide movement monitoring, which will be useful for landslide management.

SARinterferometry (InSAR) has a high potential for surface displacement mapping in the range from millimeter to meter. In this paper the potential of ERS-1/2 SARinterferometry for mapping subtle land subsidence has been investigated. A time series of ERS-1/2 SAR data from February 1993 to February 2000 is collected from measurements taken in Suzhou city, Jiangsu Province, China, eight ERS-1/2 SAR images are used to create seven interferograms, and three differential interferograms are produced using the three-pass method, which clearly show the spatial extent of land subsidence. The deformation maps are validated by leveling surveys, the correlation coefficient and standard deviation between them are 0.943 and 0.1706 respectively. Based on seven benchmarks, the subsidence rates are estimated, the overall trends are in close agreement with InSAR results. The results of study show that for the mapping of land subsidence in urban environments InSAR has a strong potential due to its cost-saving, high resolution and accuracy.

Noise reduction is one of the largest problems and biggest difficulties involved in electronic speckle pattern interferometry (ESPI). Although the second-order PDEs denoising method is a useful tool of noise reduction for the ESPI fringe patterns, its main drawback is that the second-order PDE model does not remove impulse noise, a 3×3 mean window filter is generally needed to improve the fringes. For overcome this main drawback, in this paper we apply the fourth-order PDE denoising model to the computer-simulated and experimentally obtained ESPI fringe, respectively. In both tests, the fourth-order PDE denoising model clearly outperforms the second-order PDE denoising model. Experimental results have confirmed that the fourth-order PDE denoising model is capable of removing noise in ESPI fringe images effectively.

Full Text Available Five ground-based differential interferometric synthetic aperture radar (GB-DInSAR surveys were conducted between 2005 and 2007 at the rock slope instability at Randa, Switzerland. Resultant displacement maps revealed, for the first time, the presence of an active basal rupture zone and a lateral release surface daylighting on the exposed 1991 failure scarp. Structures correlated with the boundaries of interferometric displacement domains were confirmed using a helicopter-based LiDAR DTM and oblique aerial photography. Former investigations at the site failed to conclusively detect these active release surfaces essential for kinematic and hazard analysis of the instability, although their existence had been hypothesized. The determination of the basal and lateral release planes also allowed a more accurate estimate of the currently unstable volume of 5.7±1.5 million m3. The displacement patterns reveal that two different kinematic behaviors dominate the instability, i.e. toppling above 2200 m and translational failure below. In the toppling part of the instability the areas with the highest GB-DInSAR displacements correspond to areas of enhanced micro-seismic activity. The observation of only few strongly active discontinuities daylighting on the 1991 failure surface points to a rather uniform movement in the lower portion of the instability, while most of the slip occurs along the basal rupture plane. Comparison of GB-DInSAR displacements with mapped discontinuities revealed correlations between displacement patterns and active structures, although spatial offsets occur as a result of the effective resolution of GB-DInSAR. Similarly, comparisons with measurements from total station surveys generally showed good agreement. Discrepancies arose in several cases due to local movement of blocks, the size of which could not be resolved using GB-DInSAR.

This presentation will address the 24 September 2013 Mw 7.7 Balochistan Earthquake in western Pakistan from the point of view of interferometric processing algorithms of wide-swath TerraSAR-X ScanSAR images. The algorithms are also valid for TOPS acquisition mode, the operational mode of the Sentinel-1A ESA satellite that was successfully launched in April 2014. Spectral properties of burst-mode data and an overview of the interferometric processing steps of burst-mode acquisitions, emphasizing the importance of the co-registration stage, will be provided. A co-registration approach based on incoherent cross-correlation will be presented and applied to seismic scenarios. Moreover geodynamic corrections due to differential atmospheric path delay and differential solid Earth tides are considered to achieve accuracy in the order of several centimeters. We previously derived a 3D displacement map using cross-correlation techniques applied to optical images from Landsat-8 satellite and TerraSAR-X ScanSAR amplitude images. The Landsat-8 cross-correlation measurements cover two horizontal directions, and the TerraSAR-X displacements include both horizontal along-track and slant-range (radar line-of-sight) measurements that are sensitive to vertical and horizontal deformation. It will be justified that the co-seismic displacement map from TerraSAR-X ScanSAR data may be contaminated by postseismic deformation due to the fact that the post-seismic acquisition took place one month after the main shock, confirmed in part by a TerraSAR-X stripmap interferogram (processed with conventional InSAR) covering part of the area starting on 27 September 2013. We have arranged the acquisition of a burst-synchronized stack of TerraSAR-X ScanSAR images over the affected area after the earthquake. It will be possible to apply interferometry to these data to measure the lower magnitude of the expected postseismic displacements. The processing of single interferograms will be discussed. A

Estimating the amount of erupted material during a volcanic crisis is one of the major challenges in volcano research. One way to do this and to discriminate between juvenile and non-juvenile fraction is to assess topographic changes before and after an eruption while using area-wide 3D data. LiDAR or other airborne systems may be a good source, but the recording fails when clouds due to volcanic activity obstruct the sight. In addition, costs as well as logistics are high for local observatories. When dealing with dome-building volcanoes, acquiring the data gets further complicated. As the volcano dome can change rapidly in active phases, it is nearly impossible to collect data at the right time. However, when dealing with gross volume change estimates, at least two data sets - taken directly before and after the eruption - are essential. The innovative German Earth observation mission TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is of great importance to overcome some of these problems. The two almost identical radar satellites TerraSAR-X and TanDEM-X fly in a close formation, thus recording images of the same place on the Earth surface at the same time (bistatic mode). As the radar signal penetrates clouds, digital elevation models (DEMs) of the area of investigation can be generated without problems even with cloud cover. A time series analysis of the differential DEMs therefore opens the possibility to assess volume changes at active lava domes. We choose Merapi in Indonesia and Volcán de Colima in Mexico as test sites. Both volcanoes reside in a state of long term effusive eruption, interrupted every few years by phases of dome destruction, generation of pyroclastic flows and deposition of volcanic material. The availability of extensive ground truth data for both test sites further enables to validate the spaceborne data and results. Here, we analyze lava dome changes due to the hazardous Merapi 2010 eruption. We show a series of DEMs

This paper presents a step towards a better interpretation of the scattering mechanism of different objects and their deformation histories in SARinterferometry (InSAR). The proposed technique traces individual SAR scatterer in high resolution optical images where their geometries, materials, and other properties can be better analyzed and classified. And hence scatterers of a same object can be analyzed in group, which brings us to a new level of InSAR deformation monitoring.

Along with the increasing demand for coal and the great importance attached to mine safety, gaining the information of mine surface distortion timely has already become an urgent need to guarantee the safety of mine production. D-InSAR technology is a new measure which can provide the information of surface distortion in mining areas at centi-meter level through the processing of SAR image gained from radar satellite. In addition, this technology has the advantage of monitoring large areas with no weather limit. Intro-duced the basic principle and data processing steps of D-InSAR systematically and ac-quired the differentialinterferometry based on case study data. The advantages of D-InSAR and it's usability in monitoring mining subsidence in coal mining areas were proved.

Along with the increasing demand for coal and the great importance attached to mine safety,gaining the information of mine surface distortion timely has already become an urgent need to guarantee the safety of mine production.D-InSAR technology is a new measure which can provide the information of surface distortion in mining areas at centimeter level through the processing of SAR image gained from radar satellite.In addition,this technology has the advantage of monitoring large areas with no weather limit.Introduced the basic principle and data processing steps of D-InSAR systematically and acquired the differentialinterferometry based on case study data.The advantages of D-InSAR and it's usability in monitoring mining subsidence in coal mining areas were proved.

We experimentally demonstrate a fast, simple, and accurate method based on the electrical spectral interferometry for measuring the differential mode group delay (DMGD) and chromatic dispersion (CD) between the higher order modes and the fundamental mode in a 5-km few-mode fiber (FMF). The interferogram information of multiple modes of the measured FMF is recorded and used to deduce the relative delay by applying the FFT processing with a simple mathematical algorithm. Based on the acquired relative delay of different fiber modes, the DMGD and CD can be obtained about (2.27 to 2.36) ps/m, (1.4 to 2.3) ps/nm.km for LP11 mode and (4.56 to 4.68) ps/m, (-1.1 to 1) ps/nm.km for LP21 mode, respectively, for this tested FMF. At the same time, a precision of ±0.0015 ps/m for DMGD measurement has been achieved. The experimental results show that the demonstrated method could be a good solution to the characterization of FMF used in large capacity SDM transmission systems.

Differential synthetic aperture radar interferometry (InSAR) has already proven its potential for ground subsidence monitoring. In recent years Multi-Temporal InSAR technology has been rapid development. Coherence of interferogram is an important indicator to measure the interferometric phase in the Multi-Temporal InSAR system. This paper study the effect of the Spatial-Temporal baseline on coherence for SAR images in Multi-Temporal InSAR processing base on the aspect of statistics. on the basis of a large amount of data, a formula for calculating coherence for SAR images was deduced which it correspond to the relationship between Spatial-Temporal baseline and the coherence of interferogram. This formula can optimize the selection of interference image pairs during processing Multi-Temporal InSAR. To determine whether this formula is useful, two methods of interference image pairs selection was used, one is the formula to optimize the selection, another is the traditional fixed threshold method. The author compared the coherence of Interferogram to judge the merits of the two methods. The results indicate that the formula not only select more interferogram from interferogram stack, but also increase the number of highly coherent points. And use SBAS-InSAR technique to obtain the 2010-2013 Beijing urban land subsidence information, verification monitoring accuracy by comparing level monitoring result.

The study aims at detection, mapping and monitoring of land subsidence in Jharia Coalfield, Jharkhand, India by spaceborne DInSAR, GPS and precision levelling techniques. Using multi-frequency C- and L-band DInSAR, both slowly and rapidly subsiding areas were identified and DInSAR-based subsidence maps were prepared. C-band DInSAR was found useful for detection of slowly subsiding areas whereas L-band DInSAR for rapidly subsiding and/or adverse land cover areas. Due to dynamic nature of mining and adverse land cover, temporal decorrelation poses a serious problem particularly in C-band DInSAR. Specially designed InSAR coherence guided adaptive filtering was found useful to highlight the deformation fringes. Collateral GPS and levelling observations were conducted in three test sites to validate DInSAR measurements and to determine the net displacement vectors. We observed an appreciable horizontal displacement component of land subsidence in all the test sites. For comparison of results, we calculated InSAR coherence weighted LOS displacement rates from the unwrapped differential interferograms of smaller spatial subsets and LOS projected ground-based displacement rates in three test sites. We found good agreement between DInSAR and ground-based measurements except for C-band observation in Dobari test site primarily due to large difference in observation periods and temporally inconsistent land subsidence. Collateral spaceborne and ground-based observations were also found useful for characterization of subsidence phenomena to determine net displacement vector and horizontal displacement component. In coal mining areas with spatially scattered and temporally irregular land subsidence phenomena, the adopted methodology can be used successfully for detection, mapping and monitoring of the subsiding areas vulnerable to future collapse. This will facilitate efficient planning and designing of surface infrastructures and other developmental structures in the mining

Otitis media (OM) is a highly prevalent disease that can be caused by either a bacterial or viral infection. Because antibiotics are only effective against bacterial infections, blind use of antibiotics without definitive knowledge of the infectious agent, though commonly practiced, can lead to the problems of potential harmful side effects, wasteful misuse of medical resources, and the development of antimicrobial resistance. In this work, we investigate the feasibility of using a combined Raman scattering spectroscopy and low coherence interferometry (LCI) device to differentiate OM infections caused by viruses and bacteria and improve our diagnostic ability of OM. Raman spectroscopy, an established tool for molecular analysis of biological tissue, has been shown capable of identifying different bacterial species, although mostly based on fixed or dried sample cultures. LCI has been demonstrated recently as a promising tool for determining tympanic membrane (TM) thickness and the presence and thickness of middle-ear biofilm located behind the TM. We have developed a fiber-based ear insert that incorporates spatially-aligned Raman and LCI probes for point-of-care diagnosis of OM. As shown in human studies, the Raman probe provides molecular signatures of bacterial- and viral-infected OM and normal middle-ear cavities, and LCI helps to identify depth-resolved structural information as well as guide and monitor positioning of the Raman spectroscopy beam for relatively longer signal acquisition time. Differentiation of OM infections is determined by correlating in vivo Raman data collected from human subjects with the Raman features of different bacterial and viral species obtained from cultured samples.

A new differential white light interference technique for the thickness measurements of metal foil is presented. In this work, the differential white light system consists of two Michelson interferometers in tandem,and the measured reflective surfaces are the corresponding surfaces of metal foil. Therefore, the measuring result is only relative to the thickness but not the position of metal foil. The method is non-contact and non-destructive, it has the advantages of high accuracy, fast detection, and compact structure. Theoretical analysis and preliminary experimental verifications have shown that the technique can be used to measure the thickness of foil in the range of 1 to 80 μm with accuracy better than 0.08 μm.

As part of the Ring of Fire, Shiveluch volcano is one of the largest and most active volcanoes on Kamchatka Peninsula. During the Holocene, only the southern part of the Shiveluch massive was active. Since the last Plinian eruption in 1964, the activity of Shiveluch is characterized by periods of dome growth and explosive eruptions. The recent active phase began in 1999 and continues until today. Due to the special conditions at active volcanoes, such as smoke development, danger of explosions or lava flows, as well as poor weather conditions and inaccessible area, it is difficult to observe the interaction between dome growth, dome destruction, and explosive eruptions in regular intervals. Consequently, a reconstruction of the eruption processes is hardly possible, though important for a better understanding of the eruption mechanism as well as for hazard forecast and risk assessment. A new approach is provided by the bistatic radar data acquired by the TanDEM-X satellite mission. This mission is composed of two nearly identical satellites, TerraSAR-X and TanDEM-X, flying in a close helix formation. On one hand, the radar signals penetrate clouds and partially vegetation and snow considering the average wavelength of about 3.1 cm. On the other hand, in comparison with conventional InSAR methods, the bistatic radar mode has the advantage that there are no difficulties due to temporal decorrelation. By interferometric evaluation of the simultaneously recorded SAR images, it is possible to calculate high-resolution digital elevation models (DEMs) of Shiveluch volcano and its surroundings. Furthermore, the short recurrence interval of 11 days allows to generate time series of DEMs, with which finally volumetric changes of the dome and of lava flows can be determined, as well as lava effusion rates. Here, this method is used at Shiveluch volcano based on data acquired between June 2011 and September 2014. Although Shiveluch has a fissured topography with steep slopes

In multi-temporal InSAR processing, both the Permanent Scatterer (PS) and Small BAseline Subset (SBAS) methods are optimized to obtain ground displacement rates with a nominal accuracy of millimetres per year. The PS approach extracts deformation signals on point targets by modelling and analyzing their phase value that remains stable in time for all interferograms performed with a common master image. The SBAS approach is developped to maximize the spatial and temporal coherence by construction of small baseline interferograms. In this paper, we evaluate the performance of both approaches, their limitations and their complementarity through an inter-comparison. We apply both the Gamma-IPTA chain (PS approach) and the SBAS approach developped by Lopez-Quiroz et al. on 38 ENVISAT images from November 2002 to March 2007 to map the Mexico City subsidence. The subsidence rate maps obtained by both approaches are compared quantitatively and analysed at different steps of the PS approach.The difference is partly explained by errors in the spatial integration of subsidence rates in the PS approach. At a local scale, outside subsiding area, the difference standard deviation drops to 0.9 mm/yr, close to the nominal accuracy of both approaches. On the other hand, within the subsiding area, it increases to 3.6 mm/yr, that may be partly interpreted as punctual differential subsidence between various human-made structures unseen by the SBAS approach.

Filtering methods based on oriented partial differential equations (OPDEs) have been demonstrated as a powerful tool for denoising while preserving all fringes. In this paper, we first briefly review the existing OPDEs and then derive numerous possible OPDE filtering models based on the variational methods. These models include a class of new single OPDE models, a class of new selective OPDE models, a class of new coupled OPDEs, and a class of new double OPDEs. We also investigate the performance of main OPDE models, including the choices of parameters and the influences of fringe orientation and diffusion control function on filtering results via our extensive experiments. Finally, we summarize the performance of these OPDEs.

The Corvara landslide is an active, large-scale, deep-seated and slow moving earthslide of about 30 Mm3 located in the Dolomites (Italy). It is frequently damaging a national road and, occasionally, isolated buildings and recreational ski facilities. Since the mid '90s it has been mapped, dated and monitored thanks to field surveys, boreholes, radiocarbon dating, inclinometers, piezometers and periodic D-GPS measurements, carried out by the Geology and the Forestry Planning offices of the Autonomous Province of Bolzano, the Municipality of Corvara in Badia, the University of Modena and Reggio Emilia, the IRPI-CNR of Padua. In 2013, a new phase of characterization and monitoring has started which also involves the EURAC's Institute for Applied Remote Sensing, the geodesy group of University La Sapienza, the CNR-IREA of Naples and the Leica Geosystems office in Italy. This new phase of characterization and monitoring is meant to investigate the opportunities of innovative SARinterferometry, D-GPS and in-place inclinometers techniques to provide for a high frequency monitoring of the study site in support to the analysis of the investigation of forcing factors leading unsteady, nonuniform landslide motion through different seasons of the year. Monitoring results are also expected to provide a validation of innovative interferometric techniques so to fully evaluate their conformity to be used as a long-term monitoring system in land-use planning and risk management procedures. The monitoring infrastructure now integrates: 16 Corner Reflector for satellite X-Band SAR interferometric products, 13 benchmarks for D-GPS periodic surveys, three on-site GPS receivers for continuous positioning and remote ftp data pushing, two in-place inclinometers and a pressure transducer to record pore-pressure variations. The coupling of SAR-based products with GPS records is achieved using especially designed Corner Reflectors having an appendix dedicated to hold Dual-Frequency GPS

Radar interferometry (InSAR) is a valuable tool to measure surface motion. Applying time series techniques such as Persistent Scatterer Interferometry (PSI), InSAR is able to provide surface displacements maps with mm-precision. However, InSAR can still be further optimized, e.g. by exploiting

Radar interferometry (InSAR) is a valuable tool to measure surface motion. Applying time series techniques such as Persistent Scatterer Interferometry (PSI), InSAR is able to provide surface displacements maps with mm-precision. However, InSAR can still be further optimized, e.g. by exploiting spati

Airborne differential synthetic aperture radar interferometry (D-InSAR) is a kind of potential technology to survey the surface deformation. In this paper, the errors of two usually used modes of this technology, namely, two-pass and three-pass approaches, are compared and analyzed. In the analysis, all the errors are decomposed and sorted according to the principle of independence, and the coupling between motion error and other errors is considered. Based on the analysis, analytical express...

The coseismic superficial deformation at the region of Lorca (Murcia, south-eastern Spain) due to the Mw 5.1 earthquake, on 11 May 2011, was characterized by a multidisciplinary team, integrating information from DInSAR (Synthetic Aperture Radar DifferentialInterferometry) and numerical modelling techniques. Despite the moderate magnitude of the event, quantitative information was obtained from the interferometric study of a pair of TerraSAR-X images. The DInSAR results defined the trace of the fault plane and evidenced uplift of some centimetres of the hanging wall block in agreement with the estimated deformation obtained through an elastic rupture dislocation numerical model. Meanwhile, for the footwall block, interferometric results showed that tectonic deformation is masked by an important subsidence related to groundwater extraction previously identified at the area of study. Keywords: Coseismic deformation, DInSAR, Numerical dislocation model. (Author) 29 refs.

Aguascalientes valley is just one of many regions affected by ground subsidence in Mexico, results of GPS monitoring from 2003 to date and differentialSARinterferometry using Envisat archived data show subsidence maximums of 15 centimeters but with a decreasing rate with time. Recent implementation of TerraSAR-X stripmap mode images allowed a more accurate estimation of displacements, which are being used for subsidence mapping and to develop models for corrections to geodetic positions. In addition, results of the study are also being used to the development of the State's atlas of hazards and will contribute by detecting new ground failures and areas susceptible to failure.

Characterization of freestream disturbances and their effect on laminar boundary layer transition is of great importance in high-speed wind tunnel testing, where significant differences between the behavior of scale-model and free-flight transition have long been noted. However, the methods traditionally used to perform this characterization in low-speed flows present significant difficulties when applied to supersonic and especially hypersonic wind tunnels. The design and theory of a focusing laser differential interferometer (FLDI) instrument, originally invented by Smeets at the Institut Saint-Louis in the 1970s and used recently by Parziale in the CalTech T5 shock tunnel, is presented. It is a relatively-simple, non-imaging common-path interferometer for measuring refractive signals from transition and turbulence, and it has a unique ability to look through facility windows, ignore sidewall boundary-layers and vibration, and concentrate only on the refractive signal near a pair of sharp beam foci in the core flow. The instrument's low cost and ease of implementation make it a promising alternative to traditional hot-wire anemometry and particle-based methods for turbulence characterization. Benchtop experiments using a turbulent supersonic air jet demonstrate its focusing ability, frequency response, unwanted signal rejection, and ease of use. The instrument is used to optically interrogate the flow in the Penn State University Supersonic Wind Tunnel and USAF AEDC Hypervelocity Tunnel 9 for measurement of the overall intensity and spectra of freestream disturbances. Precise characterization of the strength and spectral content of the disturbances provides insight into their nature and potential effect upon boundary layer transition. A special feature of the FLDI instrument used here is the replacement of traditional fixed Wollaston prisms with variable Sanderson prisms for laser-beam separation and recombination.

Full Text Available An L band geosynchronous synthetic aperture radar (GEO SARdifferentialinterferometry system (D-InSAR will be obviously impacted by the background ionosphere, which will give rise to relative image shifts and decorrelations of the SARinterferometry (InSAR pair, and induce the interferometric phase screen errors in interferograms. However, the background ionosphere varies within the long integration time (hundreds to thousands of seconds and the extensive imaging scene (1000 km levels of GEO SAR. As a result, the conventional temporal-spatial invariant background ionosphere model (i.e., frozen model used in Low Earth Orbit (LEO SAR is no longer valid. To address the issue, we firstly construct a temporal-spatial background ionosphere variation model, and then theoretically analyze its impacts, including relative image shifts and the decorrelation of the GEO InSAR pair, and the interferometric phase screen errors, on the repeat-track GEO D-InSAR processing. The related impacts highly depend on the background ionosphere parameters (constant total electron content (TEC component, and the temporal first-order and the temporal second-order derivatives of TEC with respect to the azimuth time, signal bandwidth, and integration time. Finally, the background ionosphere data at Isla Guadalupe Island (29.02°N, 118.27°W on 7–8 October 2013 is employed for validating the aforementioned analysis. Under the selected background ionosphere dataset, the temporal-spatial background ionosphere variation can give rise to a relative azimuth shift of dozens of meters at most, and even the complete decorrelation in the InSAR pair. Moreover, the produced interferometric phase screen error corresponds to a deformation measurement error of more than 0.2 m at most, even in a not severely impacted area.

We describe a novel method for skeletonization of gray-scale electronic speckle pattern interferometry (ESPI) fringe patterns. Our method is based on the gradient vector field (GVF). We propose a new partial differential equation model for calculating the GVF of ESPI fringe patterns. Further, we propose rules used to measure the possibility of each pixel on the skeleton based on the topological analysis of the GVF. The final skeletons are traced, which mimics the behavior of edge detection based on these rules. The proposed method works directly on the gray-scale images.

International audience; 2-pass Differential Synthetic Aperture Radar Interferometry (D-InSAR) processing have been successfully used by the scientific community to derive velocity fields. Nevertheless, a precise Digital Elevation Model (DEM) is necessary to remove the topographic component from the interferograms. This letter presents a novel method to detect and retrieve DEM errors by analyzing time series of differential interferograms. The principle of the method is based on the comparison...

Currently, one of the actual problems is remote monitoring of technical state of large objects. Different methods can be used for that purpose. The most promising of them relies on application of ground based synthetic aperture radars (SAR) and differentialinterferometry. We have designed and tested Ground Based Noise Waveform SAR based on noise radar technology [1] and synthetic aperture antennas [2]. It enabled to build an instrument for precise all-weather monitoring of large objects in real-time. We describe main performance of ground-based interferometric SAR which uses continuous Ka-band noise waveform as a probe signal. Besides, results of laboratory trials and evaluation of its main performance are presented as well.

One of the volcanic provinces in western Saudi Arabia, Harrat Al-Shaqah (also known as Harrat Lunayyir), suffered from numerous small to moderate-size earthquakes in May-July 2009. The most intensive activity occurred on 17-19 May when six magnitude 4.6-5.7 earthquakes occurred. Following the events the Saudi Civil Protection Agency evacuated the area and relocated over 20000 people to the neighboring cities of Yanbu and Medina. The activity continued throughout June with several magnitude 4-5 earthquakes but then quieted down in July. Following the activity in mid-May we sent a request for emergency satellite radar data acquisitions to the European Space Agency and later activated an International Charter to guarantee satellite data collection of the area. We have analyzed a number of satellite radar interferograms (InSAR) of the activity and the results are outstanding, owing to the stable surface conditions of this near vegetation-free region. Interferograms spanning the activity in mid-May exhibit strong deformation that extends across a large 40 km x 40 km area, showing over a meter of WSW-ENE extension. In addition, the data show clear signs of surface faulting and graben-like subsidence in the middle of the deformed area with the graben subsidence exceeding 50 cm. The deformation appears to be caused by a near-vertical dike intrusion with a WNW-ESE orientation, parallel to the Red Sea rift, and the intruded volume is of the order of 0.1 cubic km. The dike caused faulting on graben-forming normal faults. The shallowest part of the dike appears to have reached within only 2-3 km of the surface, right below where the graben is the narrowest and under an area with a number of cinder cones from previous volcanic events. The dike appears to have continued to grow after the initial strong phase of activity in mid-May, as a deformation interferogram spanning the time period from the end of may until early July shows similar deformation pattern, although with a much

概要叙述了差分合成孔径雷达（D-InSAR）的技术原理和数据处理方法，介绍了 D-InSAR 在地表形变监测中的应用技术和方法，针对研究区域的地表沉降特点选择常规 D-InSAR 和永久性散射体干涉测量（PSI）作为 InSAR 差分处理方式，分析并选取适合本项目研究的 InSAR 雷达数据，对兖州－济宁区域因煤矿开采产生的地表缓慢沉降和快速沉降进行数据分析并得出结论，达到了研究的目的。%This paper briefly described the principle and data processing methods of the Differential Interferometric SAR(D-InSAR)technology,and introduced the application techniques and methods of D-InSAR on monitoring of the ground surface deformation.According to the characteristics of the ground surface subsidence in study area,we choosed conventional D-InSAR and Permanent Scatterer Interferometry(PSI)as the InSARdifferential treatment,and analyzed and selected the InSAR radar data that is suitable for the study.Finally,we have drawn some conclusions by analyzing data of both the slow and rapid ground surface subsidence caused by the coal mining in Yanzhou-Jining area,and have achieved the purpose of the research.

This contribution will provide an overview on the evolution of the space-borne Differential Synthetic Aperture Radar Interferometry (DInSAR) scenario in the last 25 years. The DInSAR techniques have continuously evolved during the past decades, becoming important "tools" for the investigation of Earth surface deformation. Indeed, they are widely exploited both for studying the deformation phenomena relevant to natural events (i.e., earthquakes, volcanic unrests, landslides) and for analyzing displacements due to anthropogenic actions, such as underground resources exploitation. Originally, the DInSAR methodology has been successfully applied to analyze single deformation episodes thanks to its capability to generate spatially dense deformation maps of large areas, with centimeter to millimeter accuracy. However, benefiting from the availability of large SAR data archives, the interest of the scientific community has progressively moved towards the study of the temporal evolution of the detected displacements. To do this, advanced DInSAR techniques have been developed, allowing the computation of deformation time series from multi-temporal sequences of SAR images relevant to the areas of interest. This contribution will start by briefly introducing the basic rationale of the DInSAR methods for the investigation of single surface deformation episodes and their temporal evolution. Subsequently, a series of results will be presented to analyze the DInSAR scenario evolution moving from the first generation SAR sensors, as for the case of ERS-1/2 systems of ESA, to the new Sentinel-1 satellites of the COPERNICUS Programme of the European Union, highlighting the achieved drastic improvements of the surface deformation mapping capabilities. In particular, interesting results will be shown with reference to the earthquakes which have recently affected Central Italy.

Recent observations and experimental evidence have purported that a virus causes SARS, but such viruses have been isolated in only less than half of SARS patients in some studies and virologist Vincent Plummer of Winnipeg's National Microbiology Laboratory found that indeed 1 in 5 perfectly healthy Canadians with a history of recent travel to Asia had the virus. Therefore SARS microbiologic origins remain unclear. Outbreaks of multi-drug resistant (MDR) tuberculosis and the atypical mycobacteria simulate SARS on clinical, radiologic, epidemiologic, and diagnostic laboratory grounds and it is only logical then to include them in the differential to find a definitive cause and cure for SARS.

textabstractThe pathogenesis of severe acute respiratory syndrome coronavirus (SARS-CoV) is likely mediated by disproportional immune responses and the ability of the virus to circumvent innate immunity. Using functional genomics, we analyzed early host responses to SARS-CoV infection in the lungs o

Full Text Available This paper proposes SAR imaging algorithm with largest coherence based on the existing SAR imaging algorithm. The basic idea of SAR imaging algorithm in imaging processing is that output signal can have maximum signal-to-noise ratio (SNR by using the optimal imaging parameters. Traditional imaging algorithm can acquire the best focusing effect, but would bring the decoherence phenomenon in subsequent interference process. Algorithm proposed in this paper is that SAR echo adopts consistent imaging parameters in focusing processing. Although the SNR of the output signal is reduced slightly, their coherence is ensured greatly, and finally the interferogram with high quality is obtained. In this paper, two scenes of Envisat ASAR data in Zhangbei are employed to conduct experiment for this algorithm. Compared with the interferogram from the traditional algorithm, the results show that this algorithm is more suitable for SARinterferometry (InSAR research and application.

On the 26th December 2003 an earthquake with Mw=6.5 shook a large area of the Kerman Province in Iran. The epicenter of the devastating earthquake was located near the city of Bam. This paper described the application of differential synthetic aperture radar interferometry (D-INSAR) and ENVISAT ASAR data to map the coseismic surface deformation caused by the Bam earthquake including the interferometric data processing and results in detail. Based on the difference in the coherence images before and after the event and edge search of the deformation field, a new fault ruptured on the surface was detected and used as a data source for parameter extraction of a theoretical seismic modeling. The simulated deformation field from the model perfectly coincides with the result derived from the SAR interferometric measurement.

The properties and feasibility of L-band differential InSAR for detecting and monitoring mining-induced subsidence were systematically analyzed and demonstrated. The largest monitored subsidence gradient of 7.9×10-3 and magnitude of 91 cm were firstly derived by theoretical derivation. Then, the stronger phase maintaining capacity and weaker sensitivity to minor land subsidence compared with C-band DInSAR were illustrated by phase simulation of the actual mine subsidence. Finally, the data processing procedure of two-pass DInSAR was further refined to accurately observe subsidence of a coalfield of Jining in Northern China using 7 ALOS PALSAR images. The largest monitored subsidence magnitude of 39.22 cm and other properties were better investigated by testing results interpretation and subsidence analysis, and the absolute difference varying from 0.5 mm to 17.9 mm was obtained by comparison with leveling-measured subsidence. All of results show that L-band DInSAR technique can investigate the location, amount, area and other detailed subsidence information with relatively higher accuracy.

Full Text Available This paper presents a web tool for the unsupervised retrieval of Earth’s surface deformation from Synthetic Aperture Radar (SAR satellite data. The system is based on the implementation of the DifferentialSARInterferometry (DInSAR algorithm referred to as Parallel Small BAseline Subset (P-SBAS approach, within the Grid Processing on Demand (G-POD environment that is a part of the ESA’s Geohazards Exploitation Platform (GEP. The developed on-demand web tool, which is specifically addressed to scientists that are non-expert in DInSAR data processing, permits to set up an efficient on-line P-SBAS processing service to produce surface deformation mean velocity maps and time series in an unsupervised manner. Such results are obtained by exploiting the available huge ERS and ENVISAT SAR data archives; moreover, the implementation of the Sentinel-1 P-SBAS processing chain is in a rather advanced status and first results are already available. Thanks to the adopted strategy to co-locate both DInSAR algorithms and computational resources close to the SAR data archives, as well as the provided capability to easily generate the DInSAR results, the presented web tool may contribute to drastically expand the user community exploiting the DInSAR products and methodologies.

Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, landslides, mudflows, surface subsidence, surface cracks, surface solid waste accumulation and surface deformation. More seriously, coal mining causes groundwater to leak.Overpumping of groundwater has resulted in substantial land subsidence of the urban area in Datong City. Based on the previous geo-environmental investigation in the work area, the authors used radar remote sensing techniques such as InSAR (synthetic aperture radar interferometry) and D-InSAR(differential synthetic aperture radar interferometry), supplemented by the optical remote sensing method, for geo-environmental investigation to ascertain the geo-environmentai background of the Datong Jurassic and Carboniferous-Permian coalfield and evaluate the effects of the geohazards, thus providing a basis for the geo-environmental protection, geohazard control and prevention, land improvement and optimization of the human environment. In this study 8 cog-nominal ERS-1/2 SAR data frames during 1992 to 2003 were used, but the following processing was made: (1) the multi-temporal SAR magnitude images were used to interpret the geological structure, vegetation, micro-geomorphology and drainage system; (2) the multi-temporal InSAR coherent images were used to make a classification of surface features and evaluate the coherence change due to coal mining; and (3) the multi-temporal cog-nominal SAR images were used to complete D-InSAR processing to remove the information of differential deformation areas (sites). In the end, a ten-year time series of differential interferograms were obtained using the multi-temporal cog-nominal SAR images. In the tests, 84 deformed areas (sites) were obtained, belonging to those in 1993-1996, 1996-1997, 1997-1998,1998-2001, 1998--2002 and 2001-2003 respectively. Of the

Landslide is one of the common natural hazards in Romania, especially in the Curvature area of the Romanian Subcarpathians. In this region, landslides cause considerable damages to critical infrastructures, build-up environment and cultivated areas. Most of the slopes are affected by translational and rotational landslide types. The objective of this work is to locate and inventory landslides in the Buzau County, and possibly to characterize their dynamics. As the vegetation is abundant in the study area, series of L-band ALOS/PALSAR images are processed using advanced multi-temporal differentialSARinterferometry (DInSAR & PSI). To analyze the DInSAR results, an object-oriented segmentation method is proposed to identify possible landslide candidates in the interferograms; to analyze the PSI results, a statistical method is used to identify PS characterized by the same evolution pattern in the time series. Both techniques have proved to be able to detect unrecognised active landslides in the area, and allowed to complete existing geomorphological inventories. Around 700 new areas of landslides were detected after the analysis of the DInSAR results by an expert. However it represents 30% the zones that were detected in total. The false results remained difficult to isolate without a manual assessment. That means that applying SARinterferometry is not a sufficient tool to build exhausting inventories, and depending on the characteristics of the images (frame/track, baseline), the characteristics of the terrain (landcover, slope gradient, geomorphology) and the characteristics of the landslide (size, displacement rate), only a certain percentage (roughly less than 50%) of the already known landslides are detected with InSAR. Moreover, because of the large variety of landcover (urban, forest, cultivated areas, bare soils) and slope morphology in the study area, DInSAR and PSI techniques provide different results depending on local conditions.

This article proposes an optical flow type method for coregistration of forest remote sensing images. The principle of the algorithm called GeFolki is first explained. Results are shown on the images of the BioSAR 3 campaign, for the production of SAR interferograms, the coregistration a SAR and LIDAR image, and the coregistration an optical image and SAR image.The advantages of such an algorithm over conventional algorithms are explained. Finally, we propose various applications within the operating data for future BIOMASS mission: massive interferometry, ground truth production, upscaling by fusion of LIDAR and SAR data, and image mining.

Advanced differential Synthetic Aperture Radar (SAR) Interferometry (InSAR) usually identifies a set of algorithms, tools and methodologies for the generation of Earth's surface deformation maps and time series computed from a sequence of multi-temporal differentialSAR interferograms. Such techniques found their success on the large availability of SAR data archives acquired over time by several satellite systems. Indeed, the current radar Earth Observation (EO) scenario takes advantage of the widely diffused long-term C-band ESA (e.g. ERS-1, ERS-2 and ENVISAT) and Canadian (RADARSAT-1/2) SAR data archives, which have been acquired during the last 20 years, as well as of data sequences provided by the X-band generation SAR sensors, such as the COSMO-SkyMed (CSK) and TerraSAR-X (TSX) constellations. Moreover, a massive and ever increasing data flow will be further supplied by the recently launched (April 2014) Copernicus (European Union) SENTINEL-1A SAR satellite, which will also be paired during 2016 with the SENTINEL-1B twin system that will allow halving the constellation revisit time (from 12 to 6 days). In this context, the massive exploitation of these Big InSAR Data archives for the generation of advanced products will open new research perspectives to understand Earth's surface deformation dynamics at global scale. However, to reach this ambitious goal, Big InSAR Data has to be effectively exploited to generate accurate advanced products in short time frames. Therefore the need of new InSAR processing approaches, efficient algorithms and high performance computing facilities represents the basis for fully benefiting from such a Big Data. In this work we first present the recently proposed Parallel Small BAseline Subset (P-SBAS) InSAR algorithm that has been designed to process big volumes of InSAR data in short times and unsupervised manner by exploiting High Performance Computing (HPC) facilities. Then, we show how the P-SBAS approach is well suitable for

Environmental monitoring, earth-resource mapping, and military systems require broad-area imaging at high resolutions. Many times the imagery must be acquired in inclement weather or during night as well as day. Synthetic aperture radar (SAR) provides such a capability. SAR systems take advantage of the long-range propagation characteristics of radar signals and the complex information processing capability of modern digital electronics to provide high resolution imagery. SAR complements photographic and other optical imaging capabilities because of the minimum constrains on time-of-day and atmospheric conditions and because of the unique responses of terrain and cultural targets to radar frequencies. Interferometry is a method for generating a three-dimensional image of terrain. The height projection is obtained by acquiring two SAR images from two slightly differing locations. It is different from the common method of stereoscopic imaging for topography. The latter relies on differing geometric projections for triangulation to define the surface geometry whereas interferometry relies on differences in radar propagation times between the two SAR locations. This paper presents the capabilities of SAR, explains how SAR works, describes a few SAR applications, provides an overview of SAR development at Sandia, and briefly describes the motion compensation subsystem.

The TerraSAR-X is a German national SAR- satellite system for scientific and commercial applications. It is the continuation of the scientifically and technologically successful radar missions X-SAR (1994) and SRTM (2000) and will bring the national technology developments DESA and TOPAS into operational use. The space segment of TerraSAR-X is an advanced high-resolution X-Band radar satellite. The system design is based on a sound market analysis performed by Infoterra. The TerraSAR-X features an advanced high-resolution X-Band Synthetic Aperture Radar based on the active phased array technology which allows the operation in Spotlight-, Stripmap- and ScanSAR Mode with various polarizations. It combines the ability to acquire high resolution images for detailed analysis as well as wide swath images for overview applications. In addition, experimental modes like the Dual Receive Antenna Mode allow for full-polarimetric imaging as well as along track interferometry, i.e. moving target identification. The Ground Segment is optimized for flexible response to (scientific and commercial) User requests and fast image product turn-around times. The TerraSAR-X mission will serve two main goals. The first goal is to provide the strongly supportive scientific community with multi-mode X-Band SAR data. The broad spectrum of scientific application areas include Hydrology, Geology, Climatology, Oceanography, Environmental Monitoring and Disaster Monitoring as well as Cartography (DEM Generation) and Interferometry. The second goal is the establishment of a commercial EO-market in Europe which is driven by Infoterra. The commercial goal is the development of a sustainable EO-business so that the e.g. follow-on systems can be completely financed by industry from the profit. Due to its commercial potential, the TerraSAR-X project will be implemented based on a public-private partnership with the Astrium GmbH. This paper will describe first the mission objectives as well as the

The development of Radar Polarimetry and Radar Interferometry is advancing rapidly. Whereas with radar polarimetry, the textural fine-structure, target orientation, symmetries and material constituents can be recovered with considerable improvement above that of standard amplitude-only radar; with radar interferometry the spatial(in depth)structure can be explored. In Polarimetric Interferometric Synthetic Aperture Radar(POL-IN-SAR)Imaging, it is possible to recover such co-registered textura...

Full Text Available This study concentrates on the results of several advanced hybrid bistatic SAR experiments. The hybrid bistatic configuration applies to the case in which the transmitter and receiver are mounted on different types of platforms, e.g., spaceborne/airborne, airborne/stationary, spaceborne/stationary, and so on. Several hybrid bistatic SAR experiments have been performed successfully, i.e., TerraSAR-X/PAMIR, PAMIR/stationary, and TerraSAR-X/stationary. Furthermore, Multiple Baseline InterferometrySAR (MB-InSAR and Digital Beam-Forming (DBF technologies are validated in the TerraSAR-X/stationary configuration. Note that the DBF experiment results based on the spaceborne illuminator are discussed for the first time in SAR community. In addition, this paper emphasizes imaging geometry, image analysis, and focusing results.

We investigate and demonstrate the feasibility of using a combined Raman scattering (RS) spectroscopy and low-coherence interferometry (LCI) probe to differentiate microbial pathogens and improve our diagnostic ability of ear infections [otitis media (OM)]. While the RS probe provides noninvasive molecular information to identify and differentiate infectious microorganisms, the LCI probe helps to identify depth-resolved structural information as well as to guide and monitor positioning of the Raman spectroscopy beam for relatively longer signal acquisition times. A series of phantom studies, including the use of human middle ear effusion samples, were performed to mimic the conditions of in vivo investigations. These were also conducted to validate the feasibility of using this combined RS/LCI probe for point-of-care diagnosis of the infectious pathogen(s) in OM patients. This work establishes important parameters for future in vivo investigations of fast and accurate determination and diagnosis of infectious microorganisms in OM patients, potentially improving the efficacy and outcome of OM treatments, and importantly reducing the misuse of antibiotics in the presence of viral infections.

An epidemic of Severe Acute Respiratory Syndrome (SARS) led to the identification of an associated coronavirus, SARS-CoV. This virus evades the host innate immune response in part through the expression of its non-structural protein (nsp) 1, which inhibits both host gene expression and virus- and interferon (IFN)-dependent signaling. Thus, nsp1 is a promising target for drugs, as inhibition of nsp1 would make SARS-CoV more susceptible to the host antiviral defenses. To gain a better understanding of nsp1 mode of action, we generated and analyzed 38 mutants of the SARS-CoV nsp1, targeting 62 solvent exposed residues out of the 180 amino acid protein. From this work, we identified six classes of mutants that abolished, attenuated or increased nsp1 inhibition of host gene expression and/or antiviral signaling. Each class of mutants clustered on SARS-CoV nsp1 surface and suggested nsp1 interacts with distinct host factors to exert its inhibitory activities. Identification of the nsp1 residues critical for its activities and the pathways involved in these activities should help in the design of drugs targeting nsp1. Significantly, several point mutants increased the inhibitory activity of nsp1, suggesting that coronaviruses could evolve a greater ability to evade the host response through mutations of such residues.

Coastal geomorphology is highly variable as it is affected by sea-level changes and other naturally- and human-induced fluctuations. To effectively assess and monitor geomorphological changes in various time scales is thus critical for coastal management. Asian mega deltas are vulnerable to a sea-level rise due to its low-lying delta plain, and are dynamic region given a large amount of sediment supply. However, limited data availability and accessibility in the deltas have prevented establishment of systematic coastal monitoring. A variety of remote sensing systems can be used to monitor geomorphological changes in coastal areas as it has wide spatial coverage and high temporal repeatability. Especially, analysis using SAR (Synthetic Aperture Radar) data not affected by the cloud conditions offer potential for monitoring in the monsoon Asia region. We will present some case studies of Asian coastal regions using L-band SAR data, ALOS (Advanced Land Observing Satellite) PALSAR (Phased Array type L-band SAR) and JERS-1 (Japanese Earth Resource Satellite-1) SAR data. One example is that time-series of radar amplitude images can be used to delineate changes quantitatively of the areal extent of river-mouth bars in distributaries of the Mekong River delta. It shows that the estimated areas of river mouthbars gradually increase on an annual time scale, and seasonal variations of areas were also recognized. Another example is that differentialSARinterferometry is applied to the coast of the Yellow River delta in China. It shows very high subsidence rates, likely due to groundwater pumping. A further example is that we apply a SARinterferometry time series analysis to monitor ground deformations in the lower Chao Phraya delta plain, Thailand. A single reference time series interferogram from the stacking of unwrapped phases were applied. The subsidence and uplift pattern observed using the SARinterferometry time series analysis highlights the spatial complexity

When using differentialSARinterferometry (DInSAR) to monitor the surface deformation over a long time scale, it is often strongly affected by the spatial and temporal decorrelations and atmospheric dishomogeneities. The recently developed Permanent Scatterers (PS) technique proposed by Fertti et al. can overcome these difficulties by interpreting time-series of interferometric phase only at coherent point scatterers. In this study, we apply this PS technique using 25 ERS-1/2 scenes from 1992 to 2000 to monitor the subsidence in Suzhou. By using the linear deformation model, the deformation map in Suzhou urban area over the eight years is obtained. And the calculated results are in good agreement with the measurements of leveling.

Since the inception of the European Space Agency ERS Synthetic Aperture Radar (SAR) mission in the 1990s, radar interferometry has become an indispensable geophysical tool for measuring surface ground deformation over wide areas with high precision. Ground deformation is a key observation to study and monitoring multiple applications in geophysics such as earthquake and tectonics, volcano, land subsidence and landslides study and monitoring. Therefore, the frequent acquisition of SAR data to compute differential interferograms is a long standing goal in observational geodesy. A new mission designed by ESA, the Sentinel-1 mission would provide routinely frequent acquisitions (every 12 days) over larger areas (250-350 km). In April 2014, the first of expected four successive and overlapping similar spacecrafts was launched to start a total 20-year continuous operational mission. Terrain observation by progressive scans (TOPS) is a new radar acquisition mode, which provides with high quality radiometric radar amplitude images. TOPS mode allows us to acquire radar data over much wider areas than previous classical stripmap mode, and it is the default mode of acquisition of ESA Sentinel-1 satellite. However, due to a variable steering (ground scanning) of the antenna pattern, the corregistration of TOPSAR images result in a much higher demanding processing step. The higher precision azimuth SAR image corregistration and variable line-of-sight along azimuth direction intersect with the fact that image disparities on the order to a thousand of a pixel size also characterizes multiple geophysical phenomena (such as landslide dynamics, coseismic earthquake, fault creep or volcanic intrusions). In this paper, we present the first results using Sentinel-1 TOPS interferometry to measure an important deformation event. We successfully compute Sentinel-1 TOPS-InSAR and tested the effect of variable line-of-sight in azimuth, during the estimation of geophysical parameters. We

The Differential Synthetic Aperture Radar Interferometry (DInSAR) is widely used for surface deformation detection and monitoring.In this paper, ERS-1/2, ENVISAT and RADARSAT-2 synthetic aperture radar (SAR) images acquired between 1993 and 2014 were processed to investigate the evolution of surface deformation at the Cerro Prieto geothermal field, Baja California, Mexico. The conventional DInSAR together with the interferogram stacking method was applied. Average LOS (line of sight) displacement velocity maps were generated for different periods: 1993 - 1997, 1998 - 2000, 2004, 2005, 2007, 2009, and 2012 - 2014, revealing that the area corresponding to Cerro Prieto basin presented the important surface deformation (mainly subsidence) during the entire time of investigation. The changes in the surface deformation pattern and rate were identified. These changes have a good correlation in time with the changes of production in the Cerro Prieto geothermal field.

The crustal movements, probably motivating earthquakes, are considered as one of the main geodynamic sources. The quantitative measurements of ground surface deformations are vital for studying mechanisms of the buried faults or even estimating earthquake potential. A new space-geodetic technology, synthetic aperture radar interferometry (InSAR), can be applied to detect such large-area deformations, and has demonstrated some prominent advantages. This paper reviews the capacity and limitations of InSAR, and summarises the existing applications including some of our results in studying the earthquake-related crustal motions.Finally it gives the outlook for the future development of InSAR.

合成孔径雷达差分干涉测量（D-In SAR）技术是近几年迅速发展的一种监测地壳形变的新型测量技术，它具有高精度、全天候、可以进行大范围城市地表变形监测等优点。本文介绍了 D-In SAR 技术的基本原理、D-In SAR 技术在城市地表变形监测中的处理流程、探讨了制约 D-In SAR 技术监测城市地表变形精度的主要因素及其解决方法。%Differentialinterferometry synthetic aperture radar (D - In SAR) technology has been developing rapidly In recent years. It is a new type of measurement technology for crustal deformation with the advantage of high precision, all-weather application, and wide range monitoring. In this paper, the basic principle and monitoring process of D - In SAR technology were introduced, and the influence factors of the measurement precision were discussed.

This paper presents a differential successive approximation register analog-to-digital converter (SAR ADC) with a novel time-domain comparator design for wireless sensor networks. The prototype chip has been implemented in the UMC 0.18-μm 1P6M CMOS process. The proposed ADC achieves a peak ENOB of 7.98 at an input frequency of 39.7 kHz and sampling rate of 180 kHz. With the Nyquist input frequency, 68.49-dB SFDR, 7.97-ENOB is achieved. A simple quadrate layout is adopted to ease the routing complexity of the common-centroid symmetry layout. The ADC maintains a maximum differential nonlinearity of less than 0.08 LSB and integral nonlinearity less than 0.34 LSB by this type of layout.

Traditional community SAR/InSAR processing software tools have primarily focused on differentialinterferometry and Solid Earth applications. The InSAR Scientific Computing Environment (ISCE) was specifically designed to support the Earth Sciences user community as well as large scale operational processing tasks, thanks to its two-layered (Python+C/Fortran) architecture and modular framework. ISCE is freely distributed as a source tarball, allowing advanced users to modify and extend it for their research purposes and developing exploratory applications, while providing a relatively simple user interface for novice users to perform routine data analysis efficiently. Modular design of the ISCE library also enables easier development of applications to address the needs of Ecosystems, Cryosphere and Disaster Response communities in addition to the traditional Solid Earth applications. In this talk, we would like to emphasize the broader purview of the ISCE library and some of its unique features that sets it apart from other freely available community software like GMTSAR and DORIS, including: Support for multiple geometry regimes - Native Doppler (ALOS-1) as well Zero Doppler (ESA missions) systems. Support for data acquired by airborne platforms - e.g, JPL's UAVSAR and AirMOSS, DLR's F-SAR. Radiometric Terrain Correction - Auxiliary output layers from the geometry modules include projection angles, incidence angles, shadow-layover masks. Dense pixel offsets - Parallelized amplitude cross correlation for cryosphere / ionospheric correction applications. Rubber sheeting - Pixel-by-pixel offsets fields for resampling slave imagery for geometric co-registration/ ionospheric corrections. Preliminary Tandem-X processing support - Bistatic geometry modules. Extensibility to support other non-Solid Earth missions - Modules can be directly adopted for use with other SAR missions, e.g., SWOT. Preliminary support for multi-dimensional data products- multi-polarization, multi

While space-borne synthetic aperture radar (SAR) has evolved into a mature technology over the past two decades, there is a growing interest in interferometric SAR applications. Especially along-track interferometry with its capability to resolve the velocity of on-ground objects and ocean currents is of high interest for scientific applications. The accuracy of the resolved velocity on ground scales directly with the along-track separation between adjacent SAR antennas. Since space vehicles are quite limited in size, a formation flying approach with two SAR instruments distributed onto two spacecraft thus appears to be an innovative approach to along-track SARinterferometry. In the framework of an ESA study, this paper discusses the potential benefits, drawbacks and problems associated with a close formation flight for an along-track interferometrySAR mission. To this end, the absolute and relative orbit reconstruction requirements for the SAR processing chain are derived from basic interferometric principles as well as appropriate baselines of the satellite formation in L-Band and X-Band. A discussion of potential space-borne navigation sensors is presented along with the accuracy of state-of-the-art relative orbit reconstruction. Finally, appropriate thrusters for formation acquisition and control are discussed together with approaches to formation flying guidance and control as well as fuel consumption.

There is a huge abundance of viruses and membrane vesicles in seawater. We describe a new full-field, incoherently illuminated, shot-noise limited, common-path interferometric detection method that we couple with the analysis of Brownian motion to detect, quantify, and differentiate biotic nanoparticles. We validated the method with calibrated nanoparticles and homogeneous DNA or RNA.viruses. The smallest virus size that we characterized with a suitable signal-to-noise ratio was around 30 nm in diameter. Analysis of Brownian motions revealed anisotropic trajectories for myoviruses.We further applied the method for vesicles detection and for analysis of coastal and oligotrophic samples from Tara Oceans circumnavigation.

Full Text Available This paper presents a comprehensive overview of the surface deformation retrieval capability of the Differential Synthetic Aperture Radar Interferometry (DInSAR algorithm, referred to as Small BAseline Subset (SBAS technique, in the context of active volcanic areas. In particular, after a brief description of the algorithm some experiments relevant to three selected case-study areas are presented. First, we concentrate on the application of the SBAS algorithm to a single-orbit scenario, thus considering a set of SAR data composed by images acquired on descending orbits by the European Remote Sensing (ERS radar sensors and relevant to the Long Valley caldera (eastern California area. Subsequently, we address the capability of the SBAS technique in a multipleorbit context by referring to Mt. Etna volcano (southern Italy test site, with respect to which two different ERS data set, composed by images acquired both on ascending and descending orbits, are available. Finally, we take advantage of the capability of the algorithm to work in a multi-platform scenario by jointly exploiting two different sets of SAR images collected by the ERS and the Environment Satellite (ENVISAT radar sensors in the Campi Flegrei caldera (southern Italy area. The presented results demonstrate the effectiveness of the algorithm to investigate the deformation field in active volcanic areas and the potential of the DInSAR methodologies within routine surveillance scenario.

This paper explores the potential of using satellite radar inteferometry to monitor time-varying land movement prior to any visible tension crack signs. The idea was developed during dedicated geotechnical studies at a large open-pit lignite mine, where large slope movements (10-20 mm/day) were monitored and large fissures were observed in the immediate area outside the current pit limits. In this work, differentialinterferometry (DInSAR), using Synthetic Aperture Radar (SAR) ALOS images, was applied to monitor the progression of land movement that could potentially thwart mine operations. Early signs of land movements were captured by this technique well before their visual observation. Moreover, a qualitative comparison of DInSAR and ground geodetic measurements indicates that the technique can be used for the identification of high risk areas and, subsequently, for the optimization of the spatial distribution of the available ground monitoring equipment. Finally, quantitative land movement results from DInSAR are shown to be in accordance with simultaneous measurements obtained by ground means.

EcoSAR is a new synthetic aperture radar (SAR) instrument being developed at the NASA/ Goddard Space Flight Center (GSFC) for the polarimetric and interferometric measurements of ecosystem structure and biomass. The instrument uses a phased-array beamforming architecture and supports full polarimetric measurements and single pass interferometry. This Instrument development is part of NASA's Earth Science Technology Office Instrument Incubator Program (ESTO IIP).

It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. DifferentialSARInterferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km{sup 2}. Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the islands, where natural outcrops are more abundant. Two main classes of objects act as permanent scatterers in this area. The first are natural reflectors, such as rocks. The second are man-made reflectors, such as parts of buildings. Numerous local movements were found in the study area, relating to building subsidence, or compaction of anthropogenic fill. The dataset was divided into three groups for analysis, based upon the location of regional lineaments provided by SKB. Both statistical and geostatistical techniques were used. The median velocity of the three blocks did not differ by more than 0.2 mm/yr. This is not considered significant, given the possible magnitude of

A High Speed Railway goes across Wuqing district of Tianjin, China. Historical studies showed that the land subsidence of this area was very serious, which would give rise to huge security risk to the high speed railway. For detecting the detailed subsidence related to the high speed railway, we use the multi-temporal InSAR (MT-InSAR) technique to extract regional scale subsidence of Wuqing district. Take it into consideration that Wuqing district is a suburban region with large area of low coherence farmland, we select the temporarily coherent point InSAR (TCP-InSAR) approach for MT-InSAR analysis. The TCP-InSAR is a potential approach for detecting land subsidence in low coherence areas as it can identify and analysis coherent points between just two images and can acquire a reliable solution without conventional phase unwrapping. This paper extended the TCP-InSAR with use of ultrashort spatial baseline (USB) interferograms. As thetopographic effects are negligible in the USB interferograms, an external digital elevation model (DEM) is no longer needed in interferometric processing, and the parameters needed to be estimated were simplified at the same time. With use of 17 TerraSAR-X (TSX) images acquired from 2009 to 2010 over Wuqing district, the annual subsidence rates along the high speed railway were derived by the USB-TCPInSAR approach. Two subsidence funnels were found at ShuangJie town and around Wuqing Station with subsidence rate of -17 ∼ -27 mm/year and -7 ∼ -17 mm/year, respectively. The subsidence rates derived by USB-TCPInSAR were compared with those derived by the conventional TCP-InSAR that uses an external DEM for differentialinterferometry. The mean and the standard deviation of the differences between two types of results at 370697 TCPs are -4.43 × 10-6 mm/year and ±1.4673 mm/year, respectively. Further comparison with the subsidence results mentioned in several other studies were made, which shows good consistencies. The results verify

详细介绍了地基SAR的基本理论，结合建筑物二维和一维的实测数据，分析了其在距离向和方位向的分辨率以及形变的监测精度，说明了地基SAR在形变监测中的有效性，并对地基SAR今后的应用与发展作了初步展望。%We describe the basic theoretical principles for ground-based SAR, including stepped- frequency continuous wave, synthetic aperture radar and interferometric measurement. The anal-ysis of the measured monitoring data of a building structure in two-dimension and one-dimension shows the validity of ground-based SAR in ground deformation monitoring. We also make some preliminary look in applications and developments of ground-based SAR in future.

Wetlands are transition zones where the flow of water, the nutrient cycling, and the sun energy meet to produce a unique and very productive ecosystem. They provide critical habitat for a wide variety of plant and animal species, including the larval stages of many ocean fish. Wetlands also have a valuable economical importance, as they filter nutrients and pollutants from fresh water used by human and provide aquatic habitats for outdoor recreation, tourism, and fishing. Globally, many such regions are under severe environmental stress, mainly from urban development, pollution, and rising sea level. However, there is increasing recognition of the importance of these habitats, and mitigation and restoration activities have begun in a few regions. A key element in wetlands conservation, management, and restoration involves monitoring its hydrologic system, as the entire ecosystem depends on its water supply. Heretofore, hydrologic monitoring of wetlands are conducted by stage (water level) stations, which provide good temporal resolution, but suffer from poor spatial resolution, as stage station are typically distributed several, or even tens of kilometers, from one another. Wetland application of InSAR provides the needed high spatial resolution hydrological observations, complementing the high temporal resolution terrestrial observations. Although conventional wisdom suggests that interferometry does not work in vegetated areas, several studies have shown that both L- and C-band interferograms with short acquisition intervals (1-105 days) can maintain excellent coherence over wetlands. In this study we explore the usage of InSAR for detecting water level changes in various wetland environments around the world, including the Everglades (south Florida), Louisiana Coast (southern US), Chesapeake Bay (eastern US), Pantanal (Brazil), Okavango Delta (Botswana), and Lena Delta (Siberia). Our main study area is the Everglades wetland (south Florida), which is covered by

We present an investigation of surface deformation using DifferentialSARInterferometry (DInSAR) time-series carried out in an active open pit iron mine, the N5W, located in the Carajás Mineral Province (Brazilian Amazon region), using 33 TerraSAR-X (TSX-1) scenes. This mine has presented a historical of instability and surface monitoring measurements over sectors of the mine (pit walls) have been done based on ground based radar. Two complementary approaches were used: the standard DInSAR configuration, as an early warning of the slope instability conditions, and the DInSAR timeseries analysis. In order to decrease the topographic phase error a high resolution DEM was generated based on a stereo GeoEye-1 pair. Despite the fact that a DinSAR contains atmospheric and topographic phase artifacts and noise, it was possible to detect deformation in some interferometric pairs, covering pit benches, road ramps and waste piles. The timeseries analysis was performed using the 31 interferometric pairs, which were selected based on the highest mean coherence of a stack of 107 interferograms, presenting less phase unwrapping errors. The time-series deformation was retrieved by the Least-Squares (LS) solution using an extension of the Singular Value Decomposition (SVD), with a set of additional weighted constrain on the acceleration deformation. The atmospheric phase artifacts were filtered in the space-time domain and the DEM height errors were estimated based on the normal baseline diversity. The DInSAR time-series investigation showed good results for monitoring surface displacement in the N5W mine located in a tropical rainforest environment, providing very useful information about the ground movement for alarm, planning and risk assessment.

TanDEM-X is a high-resolution interferometric mission with the main goal of providing a global and unprecedentedly accurate digital elevation model (DEM) of the Earth surface by means of single-pass X-band SARinterferometry. Despite its usual quasi-monostatic configuration, TanDEM-X is the first genuinely bistatic SAR system in space. During its monostatic commissioning phase, the system has been mainly operated in pursuit monostatic mode. However, some pioneering bistat...

Full Text Available aims to address the known limitations of traditional dInSAR in the presence of disturbances to reflected signals due to agricultural activities by testing the polarimetric interferometry (polInSAR) technique for its ability to increase interferometric...

The core of the present study builds on ground deformation monitoring by SARInterferometry at Santorini Volcanic Complex (Greece). Dataset used for this case study, include the entire archive of ERS SAR and ENVISAT ASAR data for both ascending and descending orbits covering almost two decades of observations (1992-2010). Deformation signals of millimeter-level accuracy were retrieved from both SAR and ASAR datasets, by way of the Interferometric Stacking technique. The linear rate of differential phases and the corresponding errors were estimated by averaging the unwrapped differential interferograms. Subsequently, vertical deformation rates were calculated by the combination of LOS measurements in ascending and descending acquisition geometries. The observed ground deformation shows mainly subsidence in the central part of Santorini Caldera, at Nea Kammeni Island, equal to -5.1 ±0.7 mm/yr, and -6.3 ±1.2 mm/yr for the periods 1992-2000 and 2003-2010 respectively, while both signs of movements (uplift and subsidence) of lower scale magnitude were recognized elsewhere on the volcano. In fact, higher deformation rates for the period after 2003 (ranging between -4.6 mm/yr and 5.6 mm/yr), compared to the lower values of the period 1992-2000 (from -1.7 mm/yr to 2.7 mm/yr), indicate increase in the undergoing deformation of the volcanic complex. Finally, this work presents an attempt to obtain integrated interferometric results of ground deformation from both ERS and ENVISAT sensors in order to allow future investigations on the deformation sources of the volcanic complex, which could be further exploited in the volcanic hazard and risk assessment.

This article presents the main results of the Persistent Scatterer Interferometry Codes Cross Comparison and Certification for long term differentialinterferometry (PSIC4) project. The project was based on the validation of the PSI (Persistent Scatterer Interferometry) data with respect to levellin

The model of differential phase delay of same beam interferometry (SBI) is analyzed according to the requirement for the high accuracy ground based guidance and navigation of the lunar orbit rendezvous and docking mission.The differential phase delay measurement model of same beam interferometry is propagated based on the same wave front definition of very long baseline interferometry (VLBI).An accurate differential phase delay closure algorithm of same beam interfemmetry is derived based on the definition of the same wave front of SBI and the geometry delay closure algorithm of VLBI.The value of differential phase delay closure is calculated by using the observation data of the SELENE mission of Japan,and the result shows that the accuracy of differential phase delay closure is in the range of 0.5～1 ps.The algorithm given in the paper could evidently reduce tends of differential phase delay closure,and the validity of the measurement model is verified in this paper.It is of some significance for high accuracy ground-based navigation of the forthcoming lunar orbit rendezvous and docking mission.%针对月球轨道交会对接地面高精度引导需求,对同波束干涉测量差分相延观测模型进行分析验证.根据甚长基线干涉测量几何时延观测量同一波前的定义,推导出同波束差分时延观测量的观测模型.并提出一种精确的同波束干涉测量差分相时延闭合算法,同时结合SELENE任务实测的数据计算差分相时延闭合值,用于对观测模型进行验证.实测数据计算结果表明,采用本文提出的精确算法显著地消除同一波前差分相时延闭合值中的趋势项,差分相时延闭合值的精度在0.5ps～l ps范围内,验证了观测模型的正确性.该研究对于后续的月球交会对接地面高精度测定轨任务分析设计将具有一定的参考价值.

Full Text Available In this work, the analysis of TerraSAR-X satellite images combining both conventional and advanced Differential Synthetic Aperture Radar Interferometry (DInSAR approaches has proven to be effective to detect and monitor fast evolving mining subsidence on urban areas in the Upper Silesian Coal Basin (Poland. This region accounts for almost three million inhabitants where mining subsidence has produced severe damage to urban structures and infrastructures in recent years. Conventional DInSAR approach was used to generate 28 differential interferograms between 5 July 2011 and 21 June 2012 identifying 31 subsidence troughs that account up to 245 mm of displacement in 54 days (equivalent to 1660 mm/year. SqueeSARTM processing yielded a very dense measurement point distribution, failing to detect faster displacements than 330 mm/year, which occur within the subsidence troughs detected with conventional DInSAR. Despite this limitation, this approach was useful to delimit stable areas where mining activities are not conducted and areas affected by residual subsidence surrounding the detected subsidence troughs. These residual subsidence mining areas are located approximately 1 km away from the 31 detected subsidence troughs and account for a subsidence rate greater than 17 mm/year on average. The validation of this methodology has been performed over Bytom City were underground mining activity produced severe damages in August 2011. Conventional DInSAR permitted to successfully map subsidence troughs between July and August 2011 that coincide spatially and temporally with the evolution of underground mining excavations, as well as with the demolition of 28 buildings of Karb district. Additionally, SqueeSARTM displacement estimates were useful to delimit an area of 8.3 km2 of Bytom city that is affected by a residual mining subsidence greater than 5 mm/year and could potentially suffer damages in the midterm. The comparison between geodetic data and

Full Text Available In today’s urbanizing world, home of 28 megacities, there is a growing need for tools to assess urban policies and support the design and implementation of effective development strategies. Unsustainable practices of urbanization bring major implications for land and environment, and cause a dramatic increase of urban vulnerability to natural hazards. In Istanbul megacity, disaster risk reduction represents a challenging issue for urban managers. In this paper, we show the relevance of the space-borne DifferentialSARInterferometry (DInSAR technique as a tool for supporting risk management, and thus contributing to achieve the urban sustainability. To this aim, we use a dataset of high resolution SAR images collected by the TerraSAR-X satellite that have been processed through the advanced (multi-temporal Small BAseline Subset (SBAS—DInSAR technique, thus producing spatially-dense deformation velocity maps and associated time-series. Results allow to depict an up-to-date picture of surface deformations occurring in Istanbul, and thus to identify urban areas subject to potential risk. The joint analysis of remotely sensed measurements and ancillary data (geological and urban development information provides an opportunity for city planners and land professionals to discuss on the mutual relationship between urban development policies and natural/man-made hazards.

NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also known as differential interferometric measurements. Differentialinterferometry can provide key deformation measurements, important for the scientific studies of Earthquakes and volcanoes. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The expected performance of the flight control system will constrain the flight path to be within a 10 m diameter tube about the desired flight track. The radar wilI be designed to operate on a UAV (Unpiloted Aria1 Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus buitt by Scaled Composites or on a NASA Gulfstream III. The radar design is a fully polarimetric with an 80 MHz bandwidth (2 m range resolution) and 16 km range swath. The antenna is an electronically steered along track to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. Other features supported by the antenna include an elevation monopulse option and a pulse-to-pulse resteering capability that will enable some novel modes of operation. The system will nominally operate at 45,000 ft (13800 m). The program began out as an Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristics of the surface. This paper reviews the techniques of interferometry, systems and limitations, and applications in a rapidly growing area of science and engineering.

The Mw=7.6 Chi-Chi earthquake in Taiwan occurred in 1999 over the Chelungpu fault and caused a great surface rupture and severe damage. Differential Synthetic Aperture Radar Interferometry (DInSAR) has been applied previously to study the co-seismic ground displacements. There have however been significant limitations in the studies. First, only one-dimensional displacements along the Line-of-Sight (LOS) direction have been measured. The large horizontal displacements along the Chelungpu fault are largely missing from the measurements as the fault is nearly perpendicular to the LOS direction. Second, due to severe signal decorrelation on the hangling wall of the fault, the displacements in that area are un-measurable by differential InSAR method. We estimate the co-seismic displacements in both the azimuth and range directions with the method of SAR amplitude image matching. GPS observations at the 10 GPS stations are used to correct for the orbital ramp in the amplitude matching and to create the two-dimensional (2D) co-seismic surface displacements field using the descending ERS-2 SAR image pair. The results show that the co-seismic displacements range from about -2.0 m to 0.7 m in the azimuth direction (with the positive direction pointing to the flight direction), with the footwall side of the fault moving mainly southwards and the hanging wall side northwards. The displacements in the LOS direction range from about -0.5 m to 1.0 m, with the largest displacement occuring in the northeastern part of the hanging wall (the positive direction points to the satellite from ground). Comparing the results from amplitude matching with those from DInSAR, we can see that while only a very small fraction of the LOS displacement has been recovered by the DInSAR mehtod, the azimuth displacements cannot be well detected with the DInSAR measurements as they are almost perpendicular to the LOS. Therefore, the amplitude matching method is obviously more advantageous than the DInSAR

Coseismic deformation fields caused by the moment magnitude (Mw)7.8 mainshock and Mw7.3 aftershock of the 2015 Gorkha-Nepal earthquake are obtained by analyzing Sentinel-1A/IW ascending and descending interferometry data. Results show that the deformation field associated with the Mw7.8 mainshock roughly resembles a prolate ellipse, extending from the epicenter about 20° east by south. The main region of deformation is about 160 km by 110 km, comprising a large southern area of uplift, and a small northern area of subsidence. Assuming that rupture occurred in a homogeneous elastic half-space, the coseismic fault slip models of the mainshock and aftershock are inverted based on a shallow dip fault constrained by the three data sets, Sentinel-1A/IW descending data, ascending data, and ALOS-2 descending data, separately or in combination. Mainshock slip distributions generated from all three data sets are similar, and inversion constrained by all three in combination reveal a comprehensive fault slip model. Indeed, coseismic slip is mainly distributed within a narrow 40 km zone to the north of the Main Frontal Trust (MFT), and at 6-15 km subsurface depth. In addition, the maximum slip in this event was about 5.1 m, the Mw7.8 mainshock ruptured the deep part of the seismogenic zone, while the region between the southern boundary of the rupture area and the MFT remained locked. Therefore, a considerable earthquake risk remains to the south of Kathmandu. The inverted coseismic slip of the Mw7.3 aftershock was concentrated in a small area, close to, and southeast of the epicenter, with maximum displacement of about 3 m. Finally, because there is no overlap between the two slip areas of the mainshock and aftershock, the gap between them, about 15 km in length, has additional potential to generate future earthquakes.

The 500-km-long Boconó strike-slip fault runs as a major active fault along the backbone of the Mérida Andes fold-and-thrust belt. The recent right-lateral motion on the fault led to formation of numerous structures such as pull-apart basins which have formed in releasing bends and/or right-step offsets along the fault strands. The La González pull-apart is the biggest basin generated as an extensional strike-slip duplex in the central part of the fault. This duplex is made up of two strands of the Boconó fault as master/first-order faults, while normal right-lateral faults which formed during evolution of the basin are second-order faults. The extension of the basin is associated with seismic activities and surface offsets along the Boconó fault. InSAR investigations over a 31-month period also support active deformation within the basin. These data indicate that the La González basin is continuously being extended as a result of motion along the Boconó fault and formation of subsequent normal faults. In addition, the basin is being transversely shortened in NW-SE direction due to regional shortening across the Mérida Andes range followed by convergence between the Maracaibo microplate and the Guyana shield.

The northwestern Yunnan rift zone in the Yunnan Province of China is a seismically active region located along the western boundary of the Sichuan-Yunnan Block on the eastern margin of the Qinghai-Tibetan Plateau. An earthquake with a magnitude of 6.6 (Mw) occurred in this region on February 3, 1996. The Lijiang earthquake was the largest normal-faulting event to occur along the western boundary of the Sichuan-Yunnan Block in the last 40 years. In this study, we used L-band JERS-1 (Japanese Earth Resources Satellite-1) SAR data sets from two descending orbits to detect surface deformation signals surrounding the epicentral region in order to estimate the source parameters through an inversion of the displacement fields. The results indicated that the earthquake can be explained by slip along two segments of the ∼N-S trending listric normal fault, named the Lijiang-Daju fault. Coseismic deformation patterns and slip distributions revealed that the earthquake consisted of two sub-events, which were also suggested by seismological results. Based on an analysis of the static Coulomb stress change, the second sub-event was likely triggered by the first sub-event. The central segment of the Lijiang-Daju fault, which has an eastward-convex geometry, did not rupture during the earthquake. This phenomenon was probably related to a geometrical discontinuity at the fault-bend area of the Lijiang-Daju fault.

Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) is a new trend of SAR remote sensing technology which combined polarized multichannel information and Interferometric information. It is of great significance for extracting DEM in some regions with low precision of DEM such as vegetation coverage area and building concentrated area. In this paper we describe our experiments with high-resolution X-band full Polarimetric SAR data acquired by a dual-baseline interferometric airborne SAR system over an area of Danling in southern China. Pauli algorithm is used to generate the double polarimetric interferometry data, Singular Value Decomposition (SVD), Numerical Radius (NR) and Phase diversity (PD) methods are used to generate the full polarimetric interferometry data. Then we can make use of the polarimetric interferometric information to extract DEM with processing of pre filtering , image registration, image resampling, coherence optimization, multilook processing, flat-earth removal, interferogram filtering, phase unwrapping, parameter calibration, height derivation and geo-coding. The processing system named SARPlore has been exploited based on VC++ led by Chinese Academy of Surveying and Mapping. Finally compared optimization results with the single polarimetric interferometry, it has been observed that optimization ways can reduce the interferometric noise and the phase unwrapping residuals, and improve the precision of DEM. The result of full polarimetric interferometry is better than double polarimetric interferometry. Meanwhile, in different terrain, the result of full polarimetric interferometry will have a different degree of increase.

Monitoring of displacements affecting single buildings or human-made infrastructures is of key importance for their diagnostic and damage assessment. The evaluation of the structural damage in urban areas is a critical problem related to the complexity of soil-structure interaction. Indeed, the structural damage is influenced by several factors, such as the uniformity of the settlements, the variability on the soil property, the type of foundations, the rigidity and type of the considered structure, as well as the rate at which the settlements occur. Concerning this latter issue, settlements occurring very slowly over periods of decades or more may be tolerable by masonry or reinforced concrete structures; on the other hand, the same settlements related to a few months or a few years would result in severe structural damage. In this context, remote sensing techniques allow non-invasive and non-destructive deformation analyses over large areas by properly exploiting a large number of space-borne radar data. Within this framework, DifferentialSARInterferometry (DInSAR) has emerged as a valuable microwave methodology to detect and monitor ground displacements, with centimeter to millimeter accuracy, by exploiting the phase difference (interferogram) between two SAR images relevant to the same area. Recent developments of advanced DInSAR techniques are aimed at investigating not only single event deformation phenomena, but also the temporal evolution of the detected displacements through the generation of deformation time-series. These approaches benefit of the availability of huge archives of SAR data, including the ones acquired over the last 20 years by the Synthetic Aperture Radar (SAR) sensors on-board the ERS-1/2 and ENVISAT satellites of the European Space Agency (ESA). Among these advanced DInSAR approaches, we focus on the Small BAseline Subset (SBAS) algorithm (Berardino et al., 2002) that implements an easy combination of DInSAR data pairs characterized by

Coal fires in the Jharia coalfield pose a serious threat to India’s vital resource of primary coking coal and the regional environment. In order to undertake effective preventative measures, it is critical to detect the occurrence of subsurface coal fires and to monitor the extent of the existing ones. In this study, Differential Interferometric Synthetic Aperature Radar (DInSAR) technique has been utilized to monitor subsurface coal fires in the Jharia coalfield. Results showed that majority of the coal fire-related subsidence were concentrated on the eastern and western boundaries of the coalfield. The magnitude of subsidence observed was classified into high (10–27.8 mm), low (0–10 mm) and upliftment (−10–0 mm). The results were strongly supported by in situ observations and satellite-based thermal imagery analysis. Major subsidence was observed in the areas with repeated sightings of coal fire. Further, the study highlighted on the capability of the methodology for predicting potential coal fire zones on the basis of land surface subsidence only. The results from this study have major implications for demarcating the hazardous coal fire areas as well as effective implementation of public safety measures.

Coal fires in the Jharia coalfield pose a serious threat to India's vital resource of primary coking coal and the regional environment. In order to undertake effective preventative measures, it is critical to detect the occurrence of subsurface coal fires and to monitor the extent of the existing ones. In this study, Differential Interferometric Synthetic Aperature Radar (DInSAR) technique has been utilized to monitor subsurface coal fires in the Jharia coalfield. Results showed that majority of the coal fire-related subsidence were concentrated on the eastern and western boundaries of the coalfield. The magnitude of subsidence observed was classified into high (10-27.8 mm), low (0-10 mm) and upliftment (-10-0 mm). The results were strongly supported by in situ observations and satellite-based thermal imagery analysis. Major subsidence was observed in the areas with repeated sightings of coal fire. Further, the study highlighted on the capability of the methodology for predicting potential coal fire zones on the basis of land surface subsidence only. The results from this study have major implications for demarcating the hazardous coal fire areas as well as effective implementation of public safety measures.

First Talbot interferometry in the hard X-ray region was demonstrated using a pair of transmission gratings made by forming gold stripes on glass plates. By aligning the gratings on the optical axis of X-rays with a separation that caused the Talbot effect by the first grating, moire fringes were produced inclining one grating slightly against the other around the optical axis. A phase object placed in front of the first grating was detected by moire-fringe bending. Using the technique of phase-shifting interferometry, the differential phase corresponding to the phase object could also be measured. This result suggests that X-ray Talbot interferometry is a novel and simple method for phase-sensitive X-ray radiography. (author)

Synthetic Aperture Radar Interferometry (InSAR) techniques are increasingly applied for monitoring land subsidence. The advantages of InSAR include high accuracy and the ability to cover large areas; nevertheless, research validating the use of InSAR on building deformation is limited. In this paper, we test the monitoring capability of the InSAR in experiments using two landmark buildings; the Bohai Building and the China Theater, located in Tianjin, China. They were selected as real examples to compare InSAR and leveling approaches for building deformation. Ten TerraSAR-X images spanning half a year were used in Permanent Scatterer InSAR processing. These extracted InSAR results were processed considering the diversity in both direction and spatial distribution, and were compared with true leveling values in both Ordinary Least Squares (OLS) regression and measurement of error analyses. The detailed experimental results for the Bohai Building and the China Theater showed a high correlation between InSAR results and the leveling values. At the same time, the two Root Mean Square Error (RMSE) indexes had values of approximately 1 mm. These analyses show that a millimeter level of accuracy can be achieved by means of InSAR technique when measuring building deformation. We discuss the differences in accuracy between OLS regression and measurement of error analyses, and compare the accuracy index of leveling in order to propose InSAR accuracy levels appropriate for monitoring buildings deformation. After assessing the advantages and limitations of InSAR techniques in monitoring buildings, further applications are evaluated.

Terrain measurement and surface motion estimation are the most important applications for commercial and scientific SAR missions. In Dragon-3, we worked on these applications, especially regarding DEM generation, surface motion estimation with SAR time- series for urban subsidence monitoring and landslide motion estimation, as well as developing tomographic SAR processing methods in urban areas.

NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differentialinterferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 meter tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 meter range resolution) and 16 kilometer range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

Full Text Available Mapping deformation field time-series, including vertical and horizontal motions, is vital for landslide monitoring and slope safety assessment. However, the conventional differential synthetic aperture radar interferometry (DInSAR technique can only detect the displacement component in the satellite-to-ground direction, i.e., line-of-sight (LOS direction displacement. To overcome this constraint, a new method was developed to obtain the displacement field time series of a slope by coupling DInSAR based small baseline subset approach (DInSAR-SBAS with multiple-aperture InSAR (MAI based small baseline subset approach (MAI-SBAS. This novel method has been applied to a set of 11 observations from the phased array type L-band synthetic aperture radar (PALSAR sensor onboard the advanced land observing satellite (ALOS, spanning from 2007 to 2011, of two large-scale north–south slopes of the largest Asian open-pit mine in the Northeast of China. The retrieved displacement time series showed that the proposed method can detect and measure the large displacements that occurred along the north–south direction, and the gradually changing two-dimensional displacement fields. Moreover, we verified this new method by comparing the displacement results to global positioning system (GPS measurements.

As a new space geodetic technique, differential synthetic aperture radar interferometry (D-In-SAR) have more advantages than traditional geodetic technique such as all-weather, 24-hour continues surveying and ability to penetrate into substances on the earth. This article introduces the deformation monitoring of YAO QIAO with D-InSAR technology at the basic of explaining the principle of D-InSAR. The cause of few obvious interferometric fringes was analyzed. The precision of the observing data was then assessed compared with the ground-based leveling data, and the initial accuracy assessment is done.%合成孔径雷达差分干涉测量(D-InSAR)作为一种新型的空间测量技术,具有不受时间和空间的限制、对地物有一定的穿透性等传统测量所不可比拟的特点,作者在介绍其原理的基础上,利用差分干涉测量技术对姚桥矿区进行了变形监测,分析了不能产生明显干涉条纹的原因,并将实测水准数据和利用D-InsSAR技术得到的沉陷值相比较,进行了初步的精度评定.

The satellite data provide a new perspective to analyse and interpret environmental impact assessment as function of topography and vegetation. The main goal of this paper is to investigate the new Staring Spotlight TerraSAR-X mode capabilities to monitor land degradation in Rosia Jiu opencast area taking into account the mining engineering standards and specifications. The second goal is to relate mining activities with spatio-temporal dynamics of land degradation by using differential Synthetic Aperture Radar interferometry (DInSAR). The experimental analysis was carried out on data acquired in the LAN_2277 scientific proposal framework during 2014-2015 period. A set of 25 very height resolution SAR data gathered in the VV polarisation mode with a resolution of 0.45 m x 0.16m and an incidence angle of 37° have been used in this study. Preliminary results showed that altered terrain topography with steep slopes and deep pits has led to the layover of radar signal. Initially, ambiguous results have been obtained due to the highly dynamic character of subsidence induced by activities which imply mass mining methods. By increasing the SAR data number, the land degradation assessment has been improved. Most of the interferometric pairs have low coherence therefore the product coherence threshold was set to 0.3. A coherent and non-coherent analysis is performed to delineate land cover changes and complement the deformation model. Thus, the environmental impact of mining activities is better studied. Moreover, the monitoring of changes in pit depths, heights of stock-piles and waste dumps and levels of tailing dumps provide additional information about production data.

Full Text Available The satellite data provide a new perspective to analyse and interpret environmental impact assessment as function of topography and vegetation. The main goal of this paper is to investigate the new Staring Spotlight TerraSAR-X mode capabilities to monitor land degradation in Rosia Jiu opencast area taking into account the mining engineering standards and specifications. The second goal is to relate mining activities with spatio-temporal dynamics of land degradation by using differential Synthetic Aperture Radar interferometry (DInSAR. The experimental analysis was carried out on data acquired in the LAN_2277 scientific proposal framework during 2014-2015 period. A set of 25 very height resolution SAR data gathered in the VV polarisation mode with a resolution of 0.45 m x 0.16m and an incidence angle of 37° have been used in this study. Preliminary results showed that altered terrain topography with steep slopes and deep pits has led to the layover of radar signal. Initially, ambiguous results have been obtained due to the highly dynamic character of subsidence induced by activities which imply mass mining methods. By increasing the SAR data number, the land degradation assessment has been improved. Most of the interferometric pairs have low coherence therefore the product coherence threshold was set to 0.3. A coherent and non-coherent analysis is performed to delineate land cover changes and complement the deformation model. Thus, the environmental impact of mining activities is better studied. Moreover, the monitoring of changes in pit depths, heights of stock-piles and waste dumps and levels of tailing dumps provide additional information about production data.

Time series analysis of Synthetic Aperture Radar Interferometry (InSAR) data has become an important scientific tool for monitoring and measuring the displacement of Earth's surface due to a wide range of phenomena, including earthquakes, volcanoes, landslides, changes in ground water levels, and wetlands. Time series analysis is a product of interferometric phase measurements, which become ambiguous when the observed motion is larger than half of the radar wavelength. Thus, phase observations must first be unwrapped in order to obtain physically meaningful results. Persistent Scatterer Interferometry (PSI), Stanford Method for Persistent Scatterers (StaMPS), Short Baselines Interferometry (SBAS) and Small Temporal Baseline Subset (STBAS) algorithms solve for this ambiguity using a series of spatio-temporal unwrapping algorithms and filters. In this dissertation, I improve upon current phase unwrapping algorithms, and apply the PSI method to study subsidence in Mexico City. PSI was used to obtain unwrapped deformation rates in Mexico City (Chapter 3),where ground water withdrawal in excess of natural recharge causes subsurface, clay-rich sediments to compact. This study is based on 23 satellite SAR scenes acquired between January 2004 and July 2006. Time series analysis of the data reveals a maximum line-of-sight subsidence rate of 300mm/yr at a high enough resolution that individual subsidence rates for large buildings can be determined. Differential motion and related structural damage along an elevated metro rail was evident from the results. Comparison of PSI subsidence rates with data from permanent GPS stations indicate root mean square (RMS) agreement of 6.9 mm/yr, about the level expected based on joint data uncertainty. The Mexico City results suggest negligible recharge, implying continuing degradation and loss of the aquifer in the third largest metropolitan area in the world. Chapters 4 and 5 illustrate the link between time series analysis and three

The evolution of volcanoes is strictly related with their substratum and the regional tectonics. The link among morphology, geology and structure of volcanic edifices and the geological-structural characteristics of the basement is important to understand hazardous phenomena as flank eruptions and lateral collapses of volcanoes. The Colima Rift is an active regional structure, N-S oriented and more than 100 km long and 10 wide. This rift is filled by a ~1 km-thick sequence of quaternary lacustrine sediments, alluvium, and colluvium, mostly underling the about 3000 m thick volcanic pile of the Colima Volcanic Complex (CVC). In addition to the regional structures curved faults, roughly E-W oriented, are observed on the CVC edifice due to the spreading of the volcano moving southward on the weak basement. So in the CVC edifice and surrounding area we can observe the interaction of regional structures and volcanic ones due to the gravitational loading of the volcanic edifice on the weak substratum of the graben. To measure displacements due to magma movement at depth and interaction of regional structures and volcanic ones, SARinterferometry has proven to be a reliable method; however, andesitic stratovolcanoes like the CVC indeed,remain difficult to survey using this technique. The main causes are their specific geometry (steep topography), which induces strong tropospheric artefacts, environmental conditions (e.g., mainly vegetation, ash and/or snow cover), leading to a loss of coherency. In this work we try to detect deformations phenomena for the wide CVC using a robust multitemporal InSAR approach Differential Synthetic Aperture Radar Interferometry (DInSAR). We apply the Hooper (2008) DInSAR algorithm (StamPS/MTI) both to ENVISAT ASARr images acquired from 1993 to 2007 and to ALOS PALSAR (datasets from 2006 to 2010) in order to determine the deformation patterns in the CVC.

Full Text Available Subsidence is a natural hazard that affects wide areas in the world causing important economic costs annually. This phenomenon has occurred in the metropolitan area of Murcia City (SE Spain as a result of groundwater overexploitation. In this work aquifer system subsidence is investigated using an advanced differentialSARinterferometry remote sensing technique (A-DInSAR called Stable Point Network (SPN. The SPN derived displacement results, mainly the velocity displacement maps and the time series of the displacement, reveal that in the period 2004–2008 the rate of subsidence in Murcia metropolitan area doubled with respect to the previous period from 1995 to 2005. The acceleration of the deformation phenomenon is explained by the drought period started in 2006. The comparison of the temporal evolution of the displacements measured with the extensometers and the SPN technique shows an average absolute error of 3.9±3.8 mm. Finally, results from a finite element model developed to simulate the recorded time history subsidence from known water table height changes compares well with the SPN displacement time series estimations. This result demonstrates the potential of A-DInSAR techniques to validate subsidence prediction models as an alternative to using instrumental ground based techniques for validation.

The quantitative evaluation of ground deformation is traditionally based on in-situ surveying techniques that, through the intensive use of GPS stations, automatic total stations and levelling benchmarks, can measure up to sub-centimetre displacements. In the last decades, the extensive use of satellite remote sensing data, such as Synthetic Aperture Radar (SAR) images, has represented an important breakthrough in the context of non-invasive ground deformation analyses over large areas, thanks to their large spatial coverage and relatively short revisit time, as well as to their medium-high ground resolution. In such a context, the well-known DifferentialSARInterferometry (DInSAR) technique allows us to map and measure deformation phenomena due to both natural and man-made causes with centimetre to millimetre accuracy. The Earth Science community has a wide interest in the use of DInSAR displacement maps both for crisis management and risk mitigation activities, and for surveillance, monitoring and analysis of geophysical phenomena. In areas characterized by high level of hazards the availability of routinely generated advanced DInSAR products would allow a fast analysis of their current status, providing a near real time monitoring. Similarly, an on-demand service would allow the customization of the products by selecting the area of interest, the SAR data to be processed, and other processing parameters to be set by the users to edit/correct/improve the final products. In this work we discuss the Satellite Data Thematic Core Service of EPOS and we present the EPOSAR service. In particular, the EPOSAR service, based on the well-known DInSAR approach referred to as Small Baseline Subset (SBAS), accomplishes a shared and synergic Earth Observation (EO) service aimed at designing, implementing and harmonizing efficient satellite data processing chains capable of ingesting the significantly increased data stream expected from the ESA Sentinel-1 satellites. EPOSAR

Full Text Available In the presented research ERS1-2 and Envisat ASAR archive data were used for the periods 1993 – 2000 and 2003 – 2010. The radar images were acquired over Upper Silesia in southern Poland. DinSAR (Differential InSAR and SBAS (Small Baseline Subset methods were applied for the detection of the most subsided areas. The DinSAR images were layer stacked for an image using 26 interferometry pairs of ERS1-2 SAR and 16 pairs from Envisat ASAR images in an ascending-descending orbit combination. The stacking of these images showed the most subsided parts of these cities even under low coherent areas, but the results are less precise. In the Upper Silesian Coal Basin, intensive underground coal exploitation has resulted in several surface deformations under Bytom (~8-17 km2, Piekary Śląskie (~9-15 km2, Ruda Śląska (~32-42 km2 and Katowice (~20-23 km2 with 25-40 cm of subsidence (in general in the studied time periods. The SBAS technique has also shown that coal mining caused subsidence in the cities of Bytom, Katowice, and Piekary Śląskie of 5-7 cm/yr. The presented SBAS method did not work for low coherent areas, e.g. dense forested areas. DInSAR data also pointed to several decreasingly less active mining areas, which relate to the mine closures in Bytom and Ruda Śląska, which is also verified by the time series analysis.

Differential Synthetic Aperture Radar Interferometry (DInSAR) is an effective technique to estimate and monitor ground displacements with centimetre accuracy [1]. In the last decade, advanced DInSAR algorithms, such as the Small Baseline Subset (SBAS) [2] one that is aimed at following the temporal evolution of the ground deformation, showed to be significantly useful remote sensing tools for the geoscience communities as well as for those related to hazard monitoring and risk mitigation. DInSAR scenario is currently characterized by the large and steady increasing availability of huge SAR data archives that have a broad range of diversified features according to the characteristics of the employed sensor. Indeed, besides the old generation sensors, that include ERS, ENVISAT and RADARSAT systems, the new X-band generation constellations, such as COSMO-SkyMed and TerraSAR-X, have permitted an overall study of ground deformations with an unprecedented detail thanks to their improved spatial resolution and reduced revisit time. Furthermore, the incoming ESA Sentinel-1 SAR satellite is characterized by a global coverage acquisition strategy and 12-day revisit time and, therefore, will further contribute to improve deformation analyses and monitoring capabilities. However, in this context, the capability to process such huge SAR data archives is strongly limited by the existing DInSAR algorithms, which are not specifically designed to exploit modern high performance computational infrastructures (e.g. cluster, grid and cloud computing platforms). The goal of this paper is to present a Parallel version of the SBAS algorithm (P-SBAS) which is based on a dual-level parallelization approach and embraces combined parallel strategies [3], [4]. A detailed description of the P-SBAS algorithm will be provided together with a scalability analysis focused on studying its performances. In particular, a P-SBAS scalability analysis with respect to the number of exploited CPUs has

EMISAR is a fully polarimetric, dual frequency (L- and C-band) SAR system designed for remote sensing applications. The data are usually processed to 2×2 m resolution. The system has the capability of C-band cross-track single-pass interferometry and fully polarimetric repeat-pass interferometry....... The SAR is operated at high altitudes on a Gulfstream G-3 jet aircraft. The system is very well calibrated and has low sidelobes and low cross-polar contamination. Digital technology has been utilized to realize a flexible and highly stable radar with variable resolution, swath width, and imaging geometry....... Thermal control and several calibration loops have been built into the system to ensure system stability and absolute calibration. Accurately measured antenna gains and radiation patterns are included in the calibration. The processing system is developed to support data calibration, which is the key...

The high-mountain mass-transport systems are the results of steady mass shifts and catastrophic mass-movement events. The equilibrium of these systems is markedly influenced by ice occurrence, which makes high mountains especially sensitive to climate impacts [1]. The creeping and thawing of frozen debris, often found as permafrost, is a significant factor for the disposition of periglacial debris flows and related slope instabilities [2]. Not only instabilities of debris slopes but also instabilities of rock slopes can be connected to glacial and permafrost processes [3]. Glacier retreats, for instance, affect the stability of valley flanks, or varying ice content affects the rock hydrology. Such system interactions clearly show the urgent need of integral hazard assessments accounting for a variety of relevant processes in high mountains, also considering that a variety of natural hazards in high mountain regions are affecting human activities. Taking into account the wide-area coverage, remote-sensing techniques represent suitable tools for an integral hazard mapping and monitoring in high mountains, regions that are typically difficult to assess [4]. The focus of this contribution is on the potential and limitations of differentialSARinterferometry [5,6] for the detection and monitoring of unstable high-mountain slopes [7-11]. SAR data of the ERS and JERS satellites for the Swiss Alps have been analyzed with short baseline interferometry and point target interferometry [12.13]. Significant results for permafrost creeping are presented. The work presented here is part of the ongoing SLAM (Services for Landslide Monitoring) project supported by the European Space Agency [14].

I review the history of HBT interferometry, since its discovery in the mid 50's, up to the recent developments and results from BNL/RHIC experiments. I focus the discussion on the contributions to the subject given by members of our Brazilian group.

NASA's Jet Propulsion Laboratory is currently building a reconfigurable, polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track SAR data for differential interferometric measurements. Differentian interferometry can provide key deformation measurements, important for studies of earthquakes, volcanoes and other dynamically changing phenomena. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The expected performance of the flight control system will constrain the flight path to be within a 10 m diameter tube about the desired flight track. The radar will be designed to be operable on a UAV (Unpiloted Aria1 Vehicle) but will initially be demonstrated on a NASA Gulfstream III. The radar will be fully polarimetric, with a range bandwidth of 80 MHz (2 m range resolution), and will support a 16 km range swath. The antenna will be electronically steered along track to assure that the antenna beam can be directed independently, regardless of the wind direction and speed. Other features supported by the antenna include elevation monopulse and pulse-to-pulse re-steering capabilities that will enable some novel modes of operation. The system will nominally operate at 45,000 ft (13800 m). The program began as an Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

In recent years, many efforts have been made in order to assess forest stand parameters from remote sensing data, as a mean to estimate the above-ground carbon stock of forests in the context of the Kyoto protocol. Synthetic aperture radar interferometry (InSAR) techniques have gained traction in last decade as a viable technology for vegetation parameter estimation. Many works have shown that forest canopy height, which is a critical parameter for quantifying the terrestrial carbon cycle, can be estimated with InSAR. However, research is still needed to understand further the interaction of SAR signals with forest canopy and to develop an operational method for forestry applications. This work discusses the use of repeat pass interferometry with ALOS PALSAR (L band) HH polarized and COSMO Skymed (X band) HH polarized acquisitions over the Taxiarchis forest (Chalkidiki, Greece), in order to produce accurate digital elevation models (DEMs) and estimate canopy height with interferometric processing. The effect of wavelength-dependent penetration depth into the canopy is known to be strong, and could potentially lead to forest canopy height mapping using dual-wavelength SARinterferometry at X- and L-band. The method is based on scattering phase center separation at different wavelengths. It involves the generation of a terrain elevation model underneath the forest canopy from repeat-pass L-band InSAR data as well as the generation of a canopy surface elevation model from repeat pass X-band InSAR data. The terrain model is then used to remove the terrain component from the repeat pass interferometric X-band elevation model, so as to enable the forest canopy height estimation. The canopy height results were compared to a field survey with 6.9 m root mean square error (RMSE). The effects of vegetation characteristics, SAR incidence angle and view geometry, and terrain slope on the accuracy of the results have also been studied in this work.

We present new interferometric synthetic aperture radar (InSAR) results for the Khumbu region, Nepal, using PALSAR data from the ALOS1 satellite. Glaciers and ice-debris landforms represent a critical water resource to communities in the Himalayas and other relatively arid alpine environments. Changes in climate have impacted this resource as the volume of ice decreases. The monitoring of rock glaciers and debris covered glaciers is critical to the assessment of these natural resources and associated hazards (e.g. Glacial Lake Outburst Floods--GLOFs). Satellite data provide one means to monitor ice-containing landforms over broad regions. InSAR measures the subtle deformation of the surface, with mm precision, that is related to deformation or changes in ice volume within rock glaciers and debris-covered glaciers. While previous work in the region had used C-band (6 cm wavelength) SAR data from the ERS satellite, we utilize L-band data (24 cm) from the ALOS satellite, which provides better coherence, especially where the phase gradient is large. After processing 20 differential interferograms that span from 2008 to 2011, we focus on the 5 interferograms with the best overall coherence. Based on three 45-day interferograms and two 3-year interferograms, all of which have relatively small perpendicular baselines (glaciers. From the 3-year interferograms, we map the boundary of active movement along the perimeter of the debris-covered toe of Khumbu Glacier. Movement over this longer time period leads to a loss of coherence, clearly delimiting actively moving areas. Of particular note, active movement is detected in the glacier-moraine dam of Imja Lake, which has implications for GLOF hazard. The significant vertical relief in the Himalaya region poses a challenge for doing differential radar interferometry, as artifacts in the digital elevation model (DEM) can propagate into the differential interferograms. Additionally, large changes in topography or glacier surfaces

An approach to improve orbital state vectors by orbit error estimates derived from residual phase patterns in synthetic aperture radar interferograms is presented. For individual interferograms, an error representation by two parameters is motivated: the baseline error in cross-range and the rate of

Remote sensing techniques have demonstrated to be effective tools to support natural and man-made risk mitigation activities. Among these, the Differential Synthetic Aperture Radar (SAR) Interferometry (DInSAR) technology is largely exploited in geoscience, oil and gas extraction, and landslide fields. Recently, thanks to the large availability of high resolution SAR systems (10 m or less), as well as to the development of advanced data processing techniques, DInSAR products have also started to be effectively used for applications in urban areas to detect localized displacements affecting single buildings and infrastructures. The advanced DInSAR technique referred to as Small Baseline Subset (SBAS) (Lanari et al., 2004) allows us to generate very long deformation time series, by exploiting large SAR datasets spanning up to 20 years (Bonano et al., 2012). Thanks to its capability to investigate wide areas, the SBAS-DInSAR technique is particularly suitable to remotely analyse the structural conditions of buildings located in densely urbanized zones. In this work, we fully exploit the results achieved over the city of Rome, Italy, through the well-established SBAS-DInSAR approach, aimed at performing a quantitative assessment of structural damage in urban areas affected by ground deformation (Arangio et al., 2013). More in details, we present an innovative methodology that integrates the SBAS-DInSAR measurements within an existing model, in order to assess the damage, and possibly estimate the future structural conditions, of single buildings affected by significant foundation settlements. In particular, a semi-empirical approach, based on a laminated beam model (Finno et al., 2005), is applied to investigate the damage of buildings located in the southern part of the city. The obtained results are in substantial agreement with in situ surveys, proving that the presented approach is an effective tool for the preliminary evaluation of the structural conditions in

Terrain slopes, which can be measured with Synthetic Aperture Radar (SAR) interferometry either from a height map or from the interferometric phase gradient, were used to calculate the local incidence angle and the correct pixel area. Both are required for correct thematic interpretation of SAR data. The interferometric correlation depends on the pixel area projected on a plane perpendicular to the look vector and requires correction for slope effects. Methods for normalization of the backscatter and interferometric correlation for ERS-1 SAR are presented.

In refraction tomography, the low signal-to-noise ratio (S/N) can be a major obstacle in picking the first-break arrivals at the far-offset receivers. To increase the S/N, we evaluated iterative supervirtual refraction interferometry (ISVI), which is an extension of the supervirtual refraction interferometry method. In this method, supervirtual traces are computed and then iteratively reused to generate supervirtual traces with a higher S/N. Our empirical results with both synthetic and field data revealed that ISVI can significantly boost up the S/N of far-offset traces. The drawback is that using refraction events from more than one refractor can introduce unacceptable artifacts into the final traveltime versus offset curve. This problem can be avoided by careful windowing of refraction events.

The space-based gravitational-wave observatory LISA, a NASA-ESA mission to be launched after 2012, will achieve its optimal sensitivity using Time Delay Interferometry (TDI), a LISA-specific technique needed to cancel the otherwise overwhelming laser noise in the inter-spacecraft phase measurements. The TDI observables of the Michelson and Sagnac types have been interpreted physically as the virtual measurements of a synthesized interferometer. In this paper, I present Geometric TDI, a new an...

It has been demonstrated and recognized that radar interferometry is a promising method for the determination of digital elevation information and terrain slope from Synthetic Aperture Radar (SAR) data. An important application of Interferometric SAR (InSAR) data in areas with topographic variations is that the derived elevation and slope can be directly used for the absolute radiometric calibration of the amplitude SAR data as well as for scattering mechanisms analysis. On the other hand polarimetric SAR data has long been recognized as permitting a more complete inference of natural surfaces than a single channel radar system. In fact, imaging polarimetry provides the measurement of the amplitude and relative phase of all transmit and receive polarizations. On board the NASA DC-8 aircraft, NASA/JPL operates the multifrequency (P, L and C bands) multipolarimetric radar AIRSAR. The TOPSAR, a special mode of the AIRSAR system, is able to collect single-pass interferometric C- and/or L-band VV polarized data. A possible configuration of the AIRSAR/TOPSAR system is to acquire single-pass interferometric data at C-band VV polarization and polarimetric radar data at the two other lower frequencies. The advantage of this system configuration is to get digital topography information at the same time the radar data is collected. The digital elevation information can therefore be used to correctly calibrate the SAR data. This step is directly included in the new AIRSAR Integrated Processor. This processor uses a modification of the full motion compensation algorithm described by Madsen et al. (1993). However, the Digital Elevation Model (DEM) with the additional products such as local incidence angle map, and the SAR data are in a geometry which is not convenient, since especially DEMs must be referred to a specific cartographic reference system. Furthermore, geocoding of SAR data is important for multisensor and/or multitemporal purposes. In this paper, a procedure to

Using different combinations of 29 Advanced Synthetic Aperture Radar (ASAR) images, 43 Digital Elevations Models (DEM) were generated adopting SARInterferometry (InSAR) technique. Due to sand movement in desert terrain, there is a poor phase correlation between different SAR images. Therefore, suitable methodology for generating DEMs of Kuwait desert terrain using InSAR technique were worked out. Time series analysis was adopted to derive the best DEM out of 43 DEMs. The problems related to phase de-correlation over desert terrain are discussed. Various errors associated with the DEM generation are discussed which include atmospheric effects, penetration into soil medium, sand movement. The DEM of Shuttle Radar Topography Mission (SRTM) is used as a reference. The noise levels of DEM of SRTM are presented.

Semarang is one of the densely populated city in Central Java which is has Kaligarang's fault. It is lie in Kaligarang River and across several dense urban settlement. The position of Kaligarang's river itself divides in the direction nearly north-south city of Semarang. The impact of the fault can be seen in severals indication such as a land subsidence phenomenon in Tinjomoyo village area which is make impact to house and road destruction. In this research, we have used combination methods between InSAR, DinSAR and geomorphology (geology data) where is this techniques used to identity the fault area and estimate Kaligarang's fault movement velocity. In fault movement velocity observation, we only compute the movement in vertical with neglect horizontal movement. The data used in this study of one pair ALOS PALSAR level 1.0 which was acquired on June 8, 2007and 10 of September 2009. Besides that third ALOS PALSAR earlier, also used data of SRTM DEM 4th version, is used for the correction of the topography. The use of the three methods already mentioned earlier have different functions. For the lnSAR method used for the establishment of a digital model in Semarang. After getting high models digital city of Semarang, the identification process can be done layout, length, width and area of the Kaligarang fault using geomorphology. Results of such identification can be calculated using the rate of deformation and fault movement. From the result generated DinSAR method of land subsidence rate between 3 em to II em. To know the truth measurement that used DinSAR method, is performed with the decline of validation that measured using GPS. After validating obtained standard deviation of 3,073 em. To estimate the Kaligarang's fault pattern and direction is using the geomorphology method. The results that Kaligarang's is an active fault that has fault strike slip as fault pattern. It makes this research is useful because could be used as an inquick assessment in fault

The UAVSAR instrument, developed at NASA Jet Propulsion Lab, is a reconfigurable L-band, quad-polarimetric Synthetic Aperture Radar (SAR) developed specifically for repeat-track differentialinterferometry (InSAR). It offers resolution of approximately 5m and swaths greater than 16 km. Although designed to be flown aboard a UAV (Uninhabited Aerial Vehicle), it is currently being flown aboard a Gulfstream III in an ambitious set of campaigns around the world. The current archive from 2009 contains data from more than 100 missions from North America, Central America, the Caribbean, and Greenland. Compared with most SAR data from satellites, UAVSAR offers higher resolution, full-polarimetry, and an impressive noise floor. For scientists, these datasets present wonderful opportunities for understanding Earth processes and developing new algorithms for information extraction. Yet despite the diverse range of coverage, UAVSAR is still relatively under-utilized. In its capacity as the NASA SAR DAAC, the Alaska Satellite Facility (ASF) is interested in expanding recognition of this data and serving data products that can be readily downloaded into a Geographic Information System (GIS) environment. Two hurdles exist: one is the large size of the data products and the second is the format of the data. The data volumes are in excess of several GB; presenting slow downloads and overwhelming many software programs. Secondly, while the data is appropriately formatted for expert users, it may prove challenging for scientists who have not previously worked with SAR. This paper will address ways that ASF is working to reduce data volume while maintaining the integrity of the data. At the same time, the creation of value-added products that permit immediate visualization in a GIS environment will be described. Conversion of the UAVSAR polarimetric data to radiometrically terrain-corrected Pauli images in a GeoTIFF format will permit researchers to understand the scattering

Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field.

Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to the local infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994-1997 and 1997-2006) and detailed geological information in order to improve understanding of the temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the changes in spatial pattern and rate of the subsidence are correlated with the development of the Cerro Prieto Geothermal Field.

In recent years, Synthetic Aperture Radar (SAR) data have been widely used for scientific applications and several SAR missions were realized. The active sensor principle and the signal wavelength in the order of centimeters provide all-day and all-weather capabilities, respectively. The modern German TerraSAR-X (TSX) satellite provides high spatial resolution down to one meter. Based on such data SARInterferometry may yield high quality digital surface models (DSMs), which includes points located on 3d objects such as vegetation, forest, and elevated man-made structures. By removing these points, digital elevation model (DEM) representing the bare ground of Earth is obtained. The primary objective of this paper is the validation of DEMs obtained from TSX SAR data covering Barcelona area, Spain, in the framework of a scientific project conducted by ISPRS Working Group VII/2 "SARInterferometry" that aims the evaluation of DEM derived from data of modern SAR satellite sensors. Towards this purpose, a DSM was generated with 10 m grid spacing using TSX StripMap mode SAR data and converted to a DEM by filtering. The accuracy results have been presented referring the comparison with a more accurate (10 cm-1 m) digital terrain model (DTM) derived from large scale photogrammetry. The results showed that the TSX DEM is quite coherent with the topography and the accuracy is in between ±8-10 m. As another application, the persistent scatterer interferometry (PSI) was conducted using TSX data and the outcomes were compared with a 3d city model available in Google Earth, which is known to be very precise because it is based on LIDAR data. The results showed that PSI outcomes are quite coherent with reference data and the RMSZ of differences is around 2.5 m.

Subsidence related to fluid withdrawal has occurred in numerous regions of the world. The phenomena is an important hazard closely related to the development of urban areas. The analysis of the deformations requires an extensive and continuous spatial and temporal monitoring to prevent the negative effects of such risks on structures and infrastructures. Deformation measurements are fundamental in order to identify the affected area extension, to evaluate the temporal evolution of deformation velocities and to identify the main control mechanisms. DifferentialSARinterferometry represents an advanced remote sensing tool, which can map displacements at very high spatial resolution. The Persistent Scatterer Interferometry (PSI) technique is a class of SARinterferometry that uses point-wise radar targets (PS) on the ground whose phase is not interested by temporal and geometrical decorrelation. This technique generates starting from a set of images two main products: the displacement rate along line of sight (LOS) of single PS; and the LOS displacement time series of individual PS. In this work SAR data with different spatio-temporal resolution were used to study the displacements that occur from 1992 to 2012 in the Alto Guadalentin Basin (southern Spain), where is located the city of Lorca The area is affected by the highest rate of subsidence measured in Europe (>10 cm/yr-1) related to long-term exploitation of the aquifer (González et al. 2011). The objectives of the work were 1) to analyse land subsidence evolution over a 20-year period with PSI technique; 2) to compare the spatial and temporal resolution of SAR data acquired by different sensors, 3) to investigate the causes that could explain this land motion. The SAR data have been obtained with ERS-1/2 & ENVISAT (1992-2007), ALOS PALSAR (2007-2010) and COSMO-SkyMed (2011-2012) images, processed with the Stable Point Network (SPN) technique. The PSI data obtained from different satellite from 1992 to 2012

The AEGIS experiment (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) has the aim of carrying out the first measurement of the gravitational interaction of antimatter to a precision of 1%, by applying techniques from atomic physics, laser spectroscopy and interferometry to a beam of antihydrogen atoms. A further goal of the experiment is to carry out spectroscopy of the antihydrogen atoms in flight.

Differential Synthetic Aperture Radar (SAR) interferometric (D-InSAR) data of ground surface deformation are affected by several error sources associated with image acquisitions and data processing. In this paper, we study the use of D-InSAR for quantifying land subsidence due to groundwater extract

Persistent scatterer interferometry (PSI) analysis of a large area is always a challenging task regarding the removal of the atmospheric phase component. This work presents an investigation of ground movement measurements based on a combination of differentialSARinterferometry time-series (DTS) and PSI techniques, applied on a large area of extent with open pit iron mines located in Carajás (Brazilian Amazon Region), aiming at detecting linear and nonlinear ground movement. These mines have presented a history of instability, and surface monitoring measurements over sectors of the mines (pit walls) have been carried out based on ground-based radar and total station (prisms). Using a priori information regarding the topographic phase error and a phase displacement model derived from DTS, temporal phase unwrapping in the PSI processing and the removal of the atmospheric phases can be performed more efficiently. A set of 33 TerraSAR-X (TSX-1) images, acquired during the period from March 2012 to April 2013, was used to perform this investigation. The DTS analysis was carried out on a stack of multilook unwrapped interferograms using an extension of SVD to obtain the least-square solution. The height errors and deformation rates provided by the DTS approach were subtracted from the stack of interferograms to perform the PSI analysis. This procedure improved the capability of the PSI analysis for detecting high rates of deformation, as well as increased the numbers of point density of the final results. The proposed methodology showed good results for monitoring surface displacement in a large mining area, which is located in a rain forest environment, providing very useful information about the ground movement for planning and risk control.

This book is for those who have some knowledge of optics, but little or no previous experience in interferometry. Accordingly, the carefully designed presentation helps readers easily find and assimilate the interferometric techniques they need for precision measurements. Mathematics is held to a minimum, and the topics covered are also summarized in capsule overviews at the beginning and end of each chapter. Each chapter also contains a set of worked problems that give a feel for numbers.The first five chapters present a clear tutorial review of fundamentals. Chapters six and seven discus

We use the out-of-plane electronic speckle pattern interferometry (ESPI) technique to observe cracks and fracture defects on 6061 aluminum plates under thermal stress. The geometrical shape of the ESPI pattern confirmed the existence of defects. We were able to differentiate between cracks and fracture defects using a non-contact and non-destructive technique.

This investigation in holographic interferometry concerns an approach to a systematic quasi-compensation by appropriate optical modifications at the reconstruction in order that the fringes of interference become visible in the case of large unknown object deformations. The relevant relations are established by using the aberration theory for the image formation in combination with elementary intrinsic differential geometry.

Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

In the last twenty years, Differential Synthetic Aperture Radar Interferometry (DInSAR) techniques have been widely used to investigate geological processes, such as subsidence, earthquakes and landslides, through the evaluation of earth surface displacements caused by these processes. In the study of mass movements, contribution of interferometry can be limited due to the acquisition geometry of RADAR images and the rough morphology of mountain and hilly regions which represent typical landslide-prone areas. In this study, the advanced DInSAR techniques (i.e. Small Baseline Subset and Persistent Scatterers techniques), available in SARscape software, are used. These methods involve the use of multiple acquisitions stacks (large SAR temporal series) allowing improvements and refinements in landslide identification, characterization and hazard evaluation at the basin scale. Potential and limits of above mentioned techniques are outlined and discussed. The study area is the Agno Valley, located in the North-Eastern sector of Italian Alps and included in the Vicenza Province (Veneto Region, Italy). This area and the entire Vicenza Province were hit by an exceptional rainfall event on November 2010 that triggered more than 500 slope instabilities. The main aim of the work is to verify if spatial information available before the rainfall event, including ERS and ENVISAT RADAR data from 1992 to 2010, were able to predict the landslides occurred in the study area, in order to implement an effectiveness forecasting model. In the first step of the work a susceptibility analysis is carried out using landslide dataset from the IFFI project (Inventario Fenomeni Franosi in Italia, Landslide Italian Inventory) and related predisposing factors, which consist of morphometric (elevation, slope, aspect and curvature) and non-morphometric (land use, distance of roads and distance of river) factors available from the Veneto Region spatial database. Then, to test the prediction, the

Full Text Available In this work, we investigate the temporal evolution of ground deformation affecting the ocean-reclaimed lands of the Shanghai (China megacity, from 2007 to 2016, by applying the Differential Synthetic Aperture Radar Interferometry (DInSAR technique known as the Small BAseline Subset (SBAS algorithm. For the analysis, we exploited two sets of non-time-overlapped synthetic aperture radar (SAR data, acquired from 2007 to 2010, by the ASAR/ENVISAT (C-band instrument, and from 2014 to 2016 by the X-band COSMO-SkyMed (CSK sensors. The long time gap (of about three years existing between the available C- and X-band datasets made the generation of unique displacement time-series more difficult. Nonetheless, this problem was successfully solved by benefiting from knowledge of time-dependent geotechnical models, which describe the temporal evolution of the expected deformation affecting Shanghai’s ocean-reclaimed platforms. The combined ENVISAT/CSK (vertical deformation time-series were analyzed to gain insight into the future evolution of displacement signals within the investigated area. As an outcome, we find that ocean-reclaimed lands in Shanghai experienced, between 2007 and 2016, average cumulative (vertical displacements extending down to 25 centimeters.

Despite the many applications of time series interferometric synthetic aperture radar (TS-InSAR) techniques in geophysical problems, error analysis and assessment have been largely overlooked. Tropospheric propagation error is still the dominant error source of InSAR observations. However, the spatiotemporal variation of atmospheric effects is seldom considered in the present standard TS-InSAR techniques, such as persistent scatterer interferometry and small baseline subset interferometry. The failure to consider the stochastic properties of atmospheric effects not only affects the accuracy of the estimators, but also makes it difficult to assess the uncertainty of the final geophysical results. To address this issue, this paper proposes a network-based variance-covariance estimation method to model the spatiotemporal variation of tropospheric signals, and to estimate the temporal variance-covariance matrix of TS-InSAR observations. The constructed stochastic model is then incorporated into the TS-InSAR estimators both for parameters (e.g., deformation velocity, topography residual) estimation and uncertainty assessment. It is an incremental and positive improvement to the traditional weighted least squares methods to solve the multitemporal InSAR time series. The performance of the proposed method is validated by using both simulated and real datasets.

DifferentialSARInterferometry (DInSAR) is an effective tool to detect and monitor ground displacements with centimeter accuracy. The geoscience communities, as well as those related to hazard monitoring and risk mitigation, make extensively use of DInSAR. They take advantage from the current huge amount of SAR data and will benefit the incoming big data stream of Sentinel 1 system. The availability of this information makes possible the generation of Earth's surface displacement maps and time series with large spatial coverage and long time span and, often in conjunction to in-situ data, fosters advances in science. However, the managing, processing and analysis of such a huge amount of data is expected to be the major bottleneck, particularly when crisis phases occur. The emerging need of creating a common ecosystem in which data (space born and in-situ), results and processing tools are shared, is envisaged to be a successful way to address such a problem and contribute to information and knowledge spreading. The Supersites initiative as well as the ESA SuperSites Exploitation Platform (SSEP), through the ESA Grid Processing On Demand (G-POD) and Cloud Computing Operational Pilot (CIOP) projects, provide effective answers to this need. The existent tools for querying and analysing SAR data are required to be redesigned for both processing big data and for quickly replying to simultaneous user requests, mainly during emergency situations. These requirements push for the development of automatic and unsupervised processing tools as well as of scalable, widely accessible and high performance computing capabilities. The cloud-computing environment successfully responds to these objectives, particularly in case of spike and peak requests of processing resources linked to disaster events. In this work we present a parallel computational model for the Small BAseline Subset (SBAS) DInSAR algorithm as it was implemented within the computing environment provided by the

Earth Observation techniques can be very helpful for the estimation of several sources of ground deformation due to their characteristics of large spatial coverage, high resolution and cost effectiveness. In this scenario, Differential Synthetic Aperture Radar Interferometry (DInSAR) is one of the most effective methodologies for its capability to generate spatially dense deformation maps at both global and local spatial scale, with centimeter to millimeter accuracy. DInSAR exploits the phase difference (interferogram) between SAR image pairs relevant to acquisitions gathered at different times, but with the same illumination geometry and from sufficiently close flight tracks, whose separation is typically referred to as baseline. Among several, the SBAS algorithm is one of the most used DInSAR approaches and it is aimed at generating displacement time series at a multi-scale level by exploiting a set of small baseline interferograms. SBAS, and generally DInSAR, has taken benefit from the large availability of spaceborne SAR data collected along years by several satellite systems, with particular regard to the European ERS and ENVISAT sensors, which have acquired SAR images worldwide during approximately 20 years. Moreover, since 2014 the new generation of Copernicus Sentinel satellites has started to acquire data with a short revisit time (12 days) and a global coverage policy, thus flooding the scientific EO community with an unprecedent amount of data. To efficiently manage such amount of data, proper processing facilities (as those coming from the emerging Cloud Computing technologies) have to be used, as well as novel algorithms aimed at their efficient exploitation have to be developed. In this work we present a set of results achieved by exploiting a recently proposed implementation of the SBAS algorithm, namely Parallel-SBAS (P-SBAS), which allows us to effectively process, in an unsupervised way and in a limited time frame, a huge number of SAR images

Differential Synthetic Aperture Radar Interferometry (DInSAR) is a remote sensing technique that allows investigating earth surface deformation phenomena (with centimeter to millimeter accuracy) by exploiting the round-trip phase components of Synthetic Aperture Radar (SAR) images relative to an area of interest. In particular, we refer to the Small BAseline Subsets (SBAS) technique, which relies on the use of small baseline differentialSAR interferograms and on the application of the singular value decomposition (SVD) method. This technique can generate deformation velocity maps and time-series of the area of interest; moreover, it has the peculiarity to be able to work at two-scale resolution in order to investigate both spatially large deformation phenomena and localized displacements. Here we focus on the Aeolian Islands, one of the most tectonically and magmatically active zone in the Mediterranean Sea area, hosting several active volcanoes. We present preliminary results on deformation field on Lipari, Vulcano and Stromboli islands by exploiting COSMO-SkyMed (CSK) data both from ascending and descending orbits, generating time series extending from 2008 to 2013. We further combined ascending and descending data (low resolution, 20 meters) in order to separate the vertical and horizontal components of the deformation velocity. First results show that all the three islands are deforming. Lipari is principally affected by non-volcanic deformation such as gravitational instability phenomena mainly located in correspondence of coastal cliffs. On Vulcano island, we observed subsidence of the volcano La Fossa of about 4-5 cm/yr and also gravitational instability phenomena. However, the most important deformation feature is found on Stromboli along 'La Sciara del Fuoco' feature, in correspondence of lava flows. In this case, we observed subsidence of few cm/yr. By comparing InSAR results with recent structural data collected on the field at Lipari and Vulcano, we

One of the techniques that will strongly benefit from the advent of the Sentinel-1 system is DifferentialSARInterferometry (DInSAR), which has successfully demonstrated to be an effective tool to detect and monitor ground displacements with centimetre accuracy. The geoscience communities (volcanology, seismicity, …), as well as those related to hazard monitoring and risk mitigation, make extensively use of the DInSAR technique and they will take advantage from the huge amount of SAR data acquired by Sentinel-1. Indeed, such an information will successfully permit the generation of Earth's surface displacement maps and time series both over large areas and long time span. However, the issue of managing, processing and analysing the large Sentinel data stream is envisaged by the scientific community to be a major bottleneck, particularly during crisis phases. The emerging need of creating a common ecosystem in which data, results and processing tools are shared, is envisaged to be a successful way to address such a problem and to contribute to the information and knowledge spreading. The Supersites initiative as well as the ESA SuperSites Exploitation Platform (SSEP) and the ESA Cloud Computing Operational Pilot (CIOP) projects provide effective answers to this need and they are pushing towards the development of such an ecosystem. It is clear that all the current and existent tools for querying, processing and analysing SAR data are required to be not only updated for managing the large data stream of Sentinel-1 satellite, but also reorganized for quickly replying to the simultaneous and highly demanding user requests, mainly during emergency situations. This translates into the automatic and unsupervised processing of large amount of data as well as the availability of scalable, widely accessible and high performance computing capabilities. The cloud computing environment permits to achieve all of these objectives, particularly in case of spike and peak

Full Text Available The Mw=7.6 Chi-Chi earthquake in Taiwan occurred in 1999 over the Chelungpu fault and caused a great surface rupture and severe damage. Differential Synthetic Aperture Radar Interferometry (DInSAR has been applied previously to study the co-seismic ground displacements. There have however been significant limitations in the studies. First, only one-dimensional displacements along the Line-of-Sight (LOS direction have been measured. The large horizontal displacements along the Chelungpu fault are largely missing from the measurements as the fault is nearly perpendicular to the LOS direction. Second, due to severe signal decorrelation on the hangling wall of the fault, the displacements in that area are un-measurable by differential InSAR method. We estimate the co-seismic displacements in both the azimuth and range directions with the method of SAR amplitude image matching. GPS observations at the 10 GPS stations are used to correct for the orbital ramp in the amplitude matching and to create the two-dimensional (2D co-seismic surface displacements field using the descending ERS-2 SAR image pair. The results show that the co-seismic displacements range from about -2.0 m to 0.7 m in the azimuth direction (with the positive direction pointing to the flight direction, with the footwall side of the fault moving mainly southwards and the hanging wall side northwards. The displacements in the LOS direction range from about -0.5 m to 1.0 m, with the largest displacement occuring in the northeastern part of the hanging wall (the positive direction points to the satellite from ground. Comparing the results from amplitude matching with those from DInSAR, we can see that while only a very small fraction of the LOS displacement has been recovered by the DInSAR mehtod, the azimuth displacements cannot be well detected with the DInSAR measurements as they are almost perpendicular to the LOS. Therefore, the amplitude matching method is obviously more

During the severe acute respiratory syndrome (SARS) outbreak, electronic media made it possible to disseminate prevention messages rapidly. The Centers for Disease Control and Prevention’s Travelers’ Health Web site was frequently visited in the first half of 2003; more than 2.6 million visits were made to travel alerts, advisories, and other SARS-related documents. PMID:15030717

textabstractWhile it is hypothesized that Sever Acute Respiratory Syndrome (SARS) in humans is caused by a disproportional immune response illustrated by inappropriate induction of inflammatory cytokines, the exact nature of the host response to SARS coronavirus (CoV) infection causing severe

In recent years, time-series InSAR techniques have been used to study the temporal characteristics of various geophysical phenomena that produce surface deformation including earthquakes and magma migration in volcanoes. Conventional InSAR and time-series InSAR techniques have also been successfully used to study aseismic creep across faults in urban areas like the Northern Hayward Fault in California [1-3]. However, application of these methods to studying the time-dependent creep across the Central San Andreas Fault using C-band ERS and Envisat radar satellites has resulted in limited success. While these techniques estimate the average long-term far-field deformation rates reliably, creep measurement close to the fault (Exploration Agency (JAXA) in 2006, to study the temporal characteristics of creep across the Central San Andreas Fault. The longer wavelength at L-band improves observed correlation over the entire scene which significantly increased the ground area coverage of estimated deformation in each interferogram but at the cost of decreased sensitivity of interferometric phase to surface deformation. However, noise levels in our deformation estimates can be decreased by combining information from multiple SAR acquisitions using time-series InSAR techniques. We analyze 13 SAR acquisitions spanning the time-period from March 2007 to Dec 2009 using the Short Baseline Subset Analysis (SBAS) time-series InSAR technique [3]. We present detailed comparisons of estimated time-series of fault creep as a function of position along the fault including the locked section around Parkfield, CA. We also present comparisons between the InSAR time-series and GPS network observations in the Parkfield region. During these three years of observation, the average fault creep is estimated to be 35 mm/yr. References [1] Bürgmann,R., E. Fielding and, J. Sukhatme, Slip along the Hayward fault, California, estimated from space-based synthetic aperture radar interferometry

Synthetic Aperture Radar (SAR) is one of the most recent imaging technology to study the forest parameters. The invincible characteristics of microwave acquisition in cloudy regions and night imaging makes it a powerful tool to study dense forest regions. A coherent combination of radar polarimetry and interferometry (PolInSAR) enhances the accuracy of retrieved biophysical parameters. This paper attempts to address the issue of estimation of forest structural information caused due to instability of radar platforms through simulation of SAR image. The Terai Central Forest region situated at Haldwani area in Uttarakhand state of India was chosen as the study area. The system characteristics of PolInSAR dataset of Radarsat-2 SAR sensor was used for simulation process. Geometric and system specifications like platform altitude, center frequency, mean incidence angle, azimuth and range resolution were taken from metadata. From the field data it was observed that average tree height and forest stand density were 25 m and 300 stems/ha respectively. The obtained simulated results were compared with the sensor acquired master and slave intensity images. It was analyzed that for co-polarized horizontal component (HH), the mean values of simulated and real master image had a difference of 0.3645 with standard deviation of 0.63. Cross-polarized (HV) channel showed better results with mean difference of 0.06 and standard deviation of 0.1 while co-polarized vertical component (VV) did not show similar values. In case of HV polarization, mean variation between simulated and real slave images was found to be the least. Since cross-polarized channel is more sensitive to vegetation feature therefore better simulated results were obtained for this channel. Further the simulated images were processed using PolInSAR inversion modelling approach using three different techniques DEM differencing, Coherence Amplitude Inversion and Random Volume over Ground Inversion. DEM differencing

Bolometric Interferometry is a technology currently under development that will be first dedicated to the detection of B-mode polarization fluctuations in the Cosmic Microwave Background. A bolometric interferometer will have to take advantage of the wide spectral detection band of its bolometers in order to be competitive with imaging experiments. A crucial concern is that interferometers are presumed to be importantly affected by a spoiling effect known as bandwidth smearing. In this paper, we investigate how the bandwidth modifies the work principle of a bolometric interferometer and how it affects its sensitivity to the CMB angular power spectra. We obtain analytical expressions for the broadband visibilities measured by broadband heterodyne and bolometric interferometers. We investigate how the visibilities must be reconstructed in a broadband bolometric interferometer and show that this critically depends on hardware properties of the modulation phase shifters. Using an angular power spectrum estimator ...

Perfect single-crystal neutron interferometers are adversely sensitive to environmental disturbances, particularly mechanical vibrations. The sensitivity to vibrations results from the slow velocity of thermal neutrons and the long measurement time that are encountered in a typical experiment. Consequently, to achieve a good interference solutions for reducing vibration other than those normally used in optical experiments must be explored. Here we introduce a geometry for a neutron interferometer that is less sensitive to low-frequency vibrations. This design may be compared with both dynamical decoupling methods and decoherence-free subspaces that are described in quantum information processing. By removing the need for bulky vibration isolation setups, this design will make it easier to adopt neutron interferometry to a wide range of applications and increase its sensitivity.

Full Text Available Amplitude and phase statistics of SAR complex interferogram are significant in the study of interferometry and polarimetry. To reduce statistical variations, multi-look processing is adopted by averaging spatially the complex interferogram. In this study, we derive and validate three kinds of probability density functions (PDFs of multi-look interferogram for different surface feature scenes. For simple homogeneous areas with the gamma distribution intensity, a concise product-form interferometry phase PDF is derived, which is equivalent to a conventional Gauss hypergeometric PDF. For complicated areas with the K and G0 distributions intensity, two new interferometry amplitude PDFs named as Gamma-K and Gamma-G are proposed, and their phase PDFs are approximately preserved. Finally three typical areas including grass, mountain, and city are picked out from a pair of RADARSAT-2 SAR images and studied. Experimental results indicate good agreement between the computed histograms and the theoretical distributions. The results obtained can be applied to the feature classification of polarisation SAR data and the estimation of decorrelation effect of interferometric SAR.Science Journal, Vol. 64, No. 6, November 2014, pp.564-570, DOI:http://dx.doi.org/10.14429/dsj.64.4747

One of the aims of next generation optical interferometric instrumentation is to be able to make use of information contained in the visibility phase to construct high dynamic range images. Radio and optical interferometry are at the two extremes of phase corruption by the atmosphere. While in radio it is possible to obtain calibrated phases for the science objects, in the optical this is currently not possible. Instead, optical interferometry has relied on closure phase techniques to produce...

Satellite time series have already provided key measurements to retrieve information on the dynamic nature of Earth surface processes. We exploit in this work the availability of the large archives of spaceborne Synthetic Aperture Radar (SAR) data acquired by the ERS-1/2 and ENVISAT sensors of the European Space Agency (ESA) during the 1992-2009 time period, in order to investigate long term surface deformation of large areas. To achieve this result we take advantage of the DifferentialSARInterferometry (InSAR) algorithm referred to as Small BAseline Subset (SBAS) technique (Berardino et al., 2002), which allows us to generate mean deformation velocity maps and corresponding time-series by exploiting temporally overlapping SAR dataset collected by the ERS and ENVISAT sensors (Pepe et al., 2005). In particular, we focus on the results obtained by retrieving ERS-ENVISAT deformation time-series from 1992 till today in selected case studies relevant to different scenarios. We start from the analysis of the Mt. Etna volcano (Italy) and the Napoli Bay area (Italy), the latter including three volcanic systems (the Campi Flegrei caldera, the Somma-Vesuvio volcanic complex and the Ischia island) and the city of Napoli. In addition, we present the results relevant to the cities of Istanbul (Turkey) and Roma (Italy). The overall analyses are carried out by using averaged (multilook) InSAR interferograms with a spatial resolution of about 100 x 100 m. Moreover, in selected zones we further investigate localized phenomena by zooming in the areas of interest and carrying out a InSAR analysis at full spatial resolution scale (Lanari et al., 2004). In these cases we also exploit the doppler centroid variations of the post-2000 acquisitions of the ERS-2 sensor and the carrier frequency difference between the ERS-1/2 and the ENVISAT systems in order to maximize the number of investigated SAR pixels and to improve their geocoding. The presented results demonstrate the unique

Terrestrial Radar Interferometry (TRI) is a relatively new ground-based technique that combines the precision and spatial resolution of InSAR with the temporal resolution of GPS. Although TRI can be applied to a variety of fields including bridge and landslide monitoring, it is ideal for studies of the highly dynamic terminal zones of marine-terminating glaciers. Our TRI instrument is the Gamma Portable Radar Interferometer, which operates at 17.2 GHz (1.74 cm wavelength), has two receiving antennas for DEM generation, and generates amplitude and phase images at minute-scale sampling rates. Here we review preliminary results from Breiðamerkurjökull in Iceland and Helheim and Jakobshavn in Greenland. We show that the high sampling rate of the TRI can be used to observe velocity variations at the glacier terminus associated with calving, and the spatial distribution of tidal forcing. Velocity uncertainties, mainly due to atmospheric effects, are typically less than 0.05 m/d. Additionally, iceberg tracking using the amplitude imagery may provide insight into ocean currents near the terminus when fjord or lagoon conditions permit.

Full Text Available This paper describes a new approach to Persistent Scatterer Interferometry (PSI data processing and analysis, which is implemented in the PSI chain of the Geomatics (PSIG Division of CTTC. This approach includes three main processing blocks. In the first one, a set of correctly unwrapped and temporally ordered phases are derived, which are computed on Persistent Scatterers (PSs that cover homogeneously the area of interest. The key element of this block is given by the so-called Cousin PSs (CPSs, which are PSs characterized by a moderate spatial phase variation that ensures a correct phase unwrapping. This block makes use of flexible tools to check the consistency of phase unwrapping and guarantee a uniform CPS coverage. In the second block, the above phases are used to estimate the atmospheric phase screen. The third block is used to derive the PS deformation velocity and time series. Its key tool is a new 2+1D phase unwrapping algorithm. The procedure offers different tools to globally control the quality of the processing steps. The PSIG procedure has been successfully tested over urban, rural and vegetated areas using X-band PSI data. Its performance is illustrated using 28 TerraSAR-X StripMap images over the metropolitan area of Barcelona.

Along-track interferometry (ATI) has the ability to generate high-quality synthetic aperture radar (SAR) images and concurrently detect and estimate the positions of ground moving target indicators (GMTI) with moderate processing requirements. This paper focuses on several different ATI system configurations, with an emphasis on low-cost configurations employing no active electronic scanned array (AESA). The objective system has two transmit phase centers and four receive phase centers and supports agile adaptive radar behavior. The advantages of multistatic, multiple input multiple output (MIMO) ATI system configurations are explored. The two transmit phase centers can employ a ping-pong configuration to provide the multistatic behavior. For example, they can toggle between an up and down linear frequency modulated (LFM) waveform every other pulse. The four receive apertures are considered in simple linear spatial configurations. Simulated examples are examined to understand the trade space and verify the expected results. Finally, actual results are collected with the Space Dynamics Laboratorys (SDL) FlexSAR system in diverse configurations. The theory, as well as the simulated and actual SAR results, are presented and discussed.

SAR) biased downward. For infinitely deep uniform volumes, the elevation bias is often equated with the penetration depth, but this paper, it is shown that the two quantities generally differ. The interferometric bias is approximately equal to the two-way power-penetration depth if the latter is small......Natural media like cold-land ice, vegetation, and dry sand are subject to a substantial penetration at microwave frequencies. For such media, the synthetic aperture radar (SAR) ase center is located below the surface, and consequently, the surface elevation determined with SARinterferometry (In...... compared to the ambiguity height, but for increasing penetration depth, the bias approaches one quarter of the ambiguity height. Consequently, phase wrapping results even if the penetration depth exceeds ambiguity height. The ratio of the InSAR elevation bias to ambiguity height depends only on the ratio...

We apply accurate topographic phase to the Freeman-Durden decomposition for polarimetric SARinterferometry (PolInSAR) data. The cross correlation matrix obtained from PolInSAR observations can be decomposed into three scattering mechanisms matrices accounting for the odd-bounce, double-bounce and volume scattering. We estimate the phase based on the Random volume over Ground (RVoG) model, and as the initial input parameter of the numerical method which is used to solve the parameters of decomposition. In addition, the modified volume scattering model introduced by Y. Yamaguchi is applied to the PolInSAR target decomposition in forest areas rather than the pure random volume scattering as proposed by Freeman-Durden to make best fit to the actual measured data. This method can accurately retrieve the magnitude associated with each mechanism and their vertical location along the vertical dimension. We test the algorithms with L- and P- band simulated data.

Synthetic aperture radar interferometry (InSAR) has been used as an innovative technique for digital elevation model (DEM) and topographic map generation. In this paper, external DEMs are used for InSAR DEM generation to reduce the errors in data processing. The DEMs generated from repeat-pass InSAR are compared. For steep slopes and severe changes in topography, phase unwrapping quality can be improved by subtracting the phase calculated from an external DEM. It is affirmative that the absolute height accuracy of the InSAR DEM is improved by using external DEM. The data processing was undertaken without the use of ground control points and other manual operation.

ONERA has developed and operates the RAMSES experimental SAR on board a TRANSALL C160 aircraft. This system has been designed in order to analyze the effect of various parameters, such as frequency, polarization, incidence, resolution,... in the field of air-to-ground radar applications. These applications include SAR imaging for ground radar applications. These applications include SAR imaging for various purposes such as map-matching for navigation update, battlefield surveillance, reconnaissance, treaty applications... It consists of several radar sections operating over a wide range of frequency bands (L, S, C, X, Ku, Ka, W). 7 figs., 3 tabs.

We investigated the surface effects of the April 6th, 2009, L’Aquila earthquake (Mw 6.3). The earthquake affected a large area in Central Italy causing strong damage to cities and villages in the epicentral region. The main goal of this work is the detection and characterization of the geological effects, such as Deep-seated Gravitational Slope Deformation (DGSD), which are gravity-driven ground movements occurring on large (1-5 km length, 100-500 m depth and width) rock volumes. To this aim we exploited the capabilities of the new High Resolution COSMO-SkyMed SAR2000 instrument, using the DifferentialSARInterferometry (DInSAR) technique. We used a right ascending, Stripmap mode (35° incidence angle), coseimic image pair (April 4 - April 12) to measure the surface displacement. . We removed the topographic phase contribution using a detailed DEM at 5-m resolution . Local areas showing fringe complexities not directly attributed to the main tectonic pattern have been detected. By means of a geomorphological and geological analysis we interpreted such fringe patterns as due to ground displacement occurred along two different DGSD, one close to Roio Piano village, and the other North of the Barisciano village. The first DGSD is a sackung induced by the particular structural setting (down dip strata) and the high relief energy, whilst the second one appears to be a lateral spread of carbonatic bedrock. We unwrapped the interferogram to measure the local movements, and found 4-5 cm of LOS (Line Of Sight) displacement in both areas. The DGSD movement was triggered by the earthquake ground shaking, and, although in this case it did not result in a catastrophic collapse of the rock masses, it certainly indicates the presence of an increased ground shaking hazard in these areas. The L’Aquila earthquake is the second case study where the seismic triggering of DGSD has been recognized by DInSAR. It is worth noting that a step forward in terms of scale detail has been

Atom interferometry experiments are searching for evidence of chameleon scalar fields with ever-increasing precision. As experiments become more precise, so too must theoretical predictions. Previous work has made numerous approximations to simplify the calculation, which in general requires solving a 3-dimensional nonlinear partial differential equation (PDE). In this paper, we introduce a new technique for calculating the chameleonic force, using a numerical relaxation scheme on a uniform grid. This technique is more general than previous work, which assumed spherical symmetry to reduce the PDE to a 1-dimensional ordinary differential equation (ODE). We examine the effects of approximations made in previous efforts on this subject, and calculate the chameleonic force in a set-up that closely mimics the recent experiment of Hamilton et al. Specifically, we simulate the vacuum chamber as a cylinder with dimensions matching those of the experiment, taking into account the backreaction of the source mass, its o...

EUV lithography is a promising and viable candidate for circuit fabrication with 0.1-micron critical dimension and smaller. In order to achieve diffraction-limited performance, all-reflective multilayer-coated lithographic imaging systems operating near 13-nm wavelength and 0.1 NA have system wavefront tolerances of 0.27 nm, or 0.02 waves RMS. Owing to the highly-sensitive resonant reflective properties of multilayer mirrors and extraordinarily tight tolerances set forth for their fabrication, EUV optical systems require at-wavelength EUV interferometry for final alignment and qualification. This dissertation discusses the development and successful implementation of high-accuracy EUV interferometric techniques. Proof-of-principle experiments with a prototype EUV point-diffraction interferometer for the measurement of Fresnel zoneplate lenses first demonstrated sub-wavelength EUV interferometric capability. These experiments spurred the development of the superior phase-shifting point-diffraction interferometer (PS/PDI), which has been implemented for the testing of an all-reflective lithographic-quality EUV optical system. Both systems rely on pinhole diffraction to produce spherical reference wavefronts in a common-path geometry. Extensive experiments demonstrate EUV wavefront-measuring precision beyond 0.02 waves RMS. EUV imaging experiments provide verification of the high-accuracy of the point-diffraction principle, and demonstrate the utility of the measurements in successfully predicting imaging performance. Complementary to the experimental research, several areas of theoretical investigation related to the novel PS/PDI system are presented. First-principles electromagnetic field simulations of pinhole diffraction are conducted to ascertain the upper limits of measurement accuracy and to guide selection of the pinhole diameter. Investigations of the relative merits of different PS/PDI configurations accompany a general study of the most significant sources

Landslides are common phenomena that occur worldwide and are a main cause of loss of life and damage to property. The hazards associated with landslides are a challenging concern in many countries, including Italy. With 13% of the territory prone to landslides, Italy is one of the European countries with the highest landslide hazard, and on a worldwide scale, it is second only to Japan among the technologically advanced countries. Over the last 15 years, an increasing number of applications have aimed to demonstrate the applicability of images captured by space-borne Synthetic Aperture Radar (SAR) sensors in slope instability investigations. InSAR (SARInterferometry) is currently one of the most exploited techniques for the assessment of ground displacements, and it is becoming a consolidated tool for Civil Protection institutions in addressing landslide risk. We present a subset of the results obtained in Italy within the framework of SAR-based programmes and applications intended to test the potential application of C- and X-band satellite interferometry during different Civil Protection activities (namely, prevention, prevision, emergency response and post-emergency phases) performed to manage landslide risk. In all phases, different benefits can be derived from the use of SAR-based measurements, which were demonstrated to be effective in the field of landslide analysis. Analysis of satellite-SAR data is demonstrated to play a major role in the investigation of landslide-related events at different stages, including detection, mapping, monitoring, characterization and prediction. Interferometric approaches are widely consolidated for analysis of slow-moving slope deformations in a variety of environments, and exploitation of the amplitude data in SAR images is a somewhat natural complement for rapid-moving landslides. In addition, we discuss the limitations that still exist and must be overcome in the coming years to manage the transition of satellite SAR

Satellite synthetic aperture radar (SAR) interferometry is used to investigate the slowly accumulating ground settlement at the new Chek Lap Kok Airport in Hong Kong. Most of the land occupied by the airport was reclaimed from the sea and therefore certain ground settlement in the area has been expected. A pair of ERS-2 SAR images spanning nearly a year is used in the study. The high spatial resolution (20 m× 20 m) ground settlement map derived indicates that the settlement that occurred in the area over the time period is as large as 50 mm. The SAR measurement results agree with the levelling measurements at some benchmarks in the area to well within 1 cm(rms error),and the overall correlation between the two types of results is 0.89. The paper presents some brief background of interferometric SAR, and outlines the data processing methods and results.

Integer carrier phase ambiguity resolution is the key to fast and highprecision satellite positioning and navigation. It applies to a great variety of current and future models of GPS, modernized GPS and Galileo. It also applies to stacked radar interferometry for deformation monitoring, see e.g. [Hanssen, et al, 2001]. In this contribution we apply the integer least-squares' principle to the rank defect model of stacked InSAR carrier phase data. We discuss two ways of dealing with the rank defect for ambiguity resolution. One is based on the use of a priori data, the other is based on the use of an interval constraint on the deformation rate.

The objective of this project was to investigate the utility of satellite synthetic aperture radar (SAR) imagery for measurement of geophysical parameters on Alaskan glaciers relevant to their mass balance and dynamics, including: (1) the positions of firn lines (late-summer snow lines); (2) surface velocities on fast-flowing (surging) glaciers, and also on slower steady-flow glaciers; and (3) the positions and changes in the positions of glacier termini. Preliminary studies of topography and glacier surface velocity with SARinterferometry have also been carried out. This project was motivated by the relationships of multi-year to decadal changes in glacier geometry to changing climate, and the probable significant contribution of Alaskan glaciers to rising sea level.

The InSAR Scientific Computing Environment (ISCE) is a software development effort in its second year within the NASA Advanced Information Systems and Technology program. The ISCE will provide a new computing environment for geodetic image processing for InSAR sensors that will enable scientists to reduce measurements directly from radar satellites and aircraft to new geophysical products without first requiring them to develop detailed expertise in radar processing methods. The environment can serve as the core of a centralized processing center to bring Level-0 raw radar data up to Level-3 data products, but is adaptable to alternative processing approaches for science users interested in new and different ways to exploit mission data. The NRC Decadal Survey-recommended DESDynI mission will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystem. The InSAR Scientific Computing Environment is planned to become a key element in processing DESDynI data into higher level data products and it is expected to enable a new class of analyses that take greater advantage of the long time and large spatial scales of these new data, than current approaches. At the core of ISCE is both legacy processing software from the JPL/Caltech ROI_PAC repeat-pass interferometry package as well as a new InSAR processing package containing more efficient and more accurate processing algorithms being developed at Stanford for this project that is based on experience gained in developing processors for missions such as SRTM and UAVSAR. Around the core InSAR processing programs we are building object-oriented wrappers to enable their incorporation into a more modern, flexible, extensible software package that is informed by modern programming methods, including rigorous componentization of processing codes, abstraction and generalization of data models, and a robust, intuitive user interface with

Vulnerability of the US Gulf coast to inundation has received increased attention since hurricanes Katrina and Rita. Compounding effects of sea level rise, wetland loss, and regional and local subsidence makes flood protection a difficult challenge, and particularly for the New Orleans area. Key to flood protection is precise knowledge of elevations and elevation changes. Analysis of historical and continuing geodetic measurements show surprising complexity, including locations subsiding more rapidly than considered during planning of hurricane protection and coastal restoration projects. Combining traditional, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations can provide geographically dense constraints on surface deformation. The Gulf Coast environment is challenging for InSAR techniques, especially with systems not designed for interferometry. We use two InSAR capable systems, the L- band (24 cm wavelength) airborne JPL/NASA UAVSAR, and the DLR/EADS Astrium spaceborne TerraSAR X-band (3 cm wavelength), and compare results. First, we are applying pair-wise InSAR to the longer wavelength UAVSAR data to detect localized elevation changes potentially impacting flood protection infrastructure from 2009 - 2014. We focus on areas on and near flood protection infrastructure to identify changes indicative of subsidence, structural deformation, and/or seepage. The Spaceborne TerraSAR X-band SAR system has relatively frequent observations, and dense persistent scatterers in urban areas, enabling measurement of very small displacements. We compare L-band UAVSAR results with permanent scatterer (PS-InSAR) and Short Baseline Subsets (SBAS) interferometric analyses of a stack composed by 28 TerraSAR X-band images acquired over the same period. Thus we can evaluate results from the different radar frequencies and analyses techniques. Preliminary results indicate subsidence features potentially of a variety of causes, including ground water

A transition between energy levels at an avoided crossing is known as a Landau-Zener transition. When a two-level system (TLS) is subject to periodic driving with sufficiently large amplitude, a sequence of transitions occurs. The phase accumulated between transitions (commonly known as the Stueckelberg phase) may result in constructive or destructive interference. Accordingly, the physical observables of the system exhibit periodic dependence on the various system parameters. This phenomenon is often referred to as Landau-Zener-Stueckelberg (LZS) interferometry. Phenomena related to LZS interferometry occur in a variety of physical systems. In particular, recent experiments on LZS interferometry in superconducting TLSs (qubits) have demonstrated the potential for using this kind of interferometry as an effective tool for obtaining the parameters characterizing the TLS as well as its interaction with the control fields and with the environment. Furthermore, strong driving could allow for fast and reliable control of the quantum system. Here we review recent experimental results on LZS interferometry, and we present related theory.

Future extreme ultraviolet lithography (EWL) steppers will, in all likelihood, have six-mirror projection cameras. To operate at the diffraction limit over an acceptable depth of focus each aspheric mirror will have to be fabricated with an absolute figure accuracy approaching 100 pm rms. We are currently developing visible light interferometry to meet this need based on modifications of our present phase shifting diffraction interferometry (PSDI) methodology where we achieved an absolute accuracy of 250pm. The basic PSDI approach has been further simplified, using lensless imaging based on computational diffractive back-propagation, to eliminate auxiliary optics that typically limit measurement accuracy. Small remaining error sources, related to geometric positioning, CCD camera pixel spacing and laser wavelength, have been modeled and measured. Using these results we have estimated the total system error for measuring off-axis aspheric EUVL mirrors with this new approach to interferometry.

One of the aims of next generation optical interferometric instrumentation is to be able to make use of information contained in the visibility phase to construct high dynamic range images. Radio and optical interferometry are at the two extremes of phase corruption by the atmosphere. While in radio it is possible to obtain calibrated phases for the science objects, in the optical this is currently not possible. Instead, optical interferometry has relied on closure phase techniques to produce images. Such techniques allow only to achieve modest dynamic ranges. However, with high contrast objects, for faint targets or when structure detail is needed, phase referencing techniques as used in radio interferometry, should theoretically achieve higher dynamic ranges for the same number of telescopes. Our approach is not to provide evidence either for or against the hypothesis that phase referenced imaging gives better dynamic range than closure phase imaging. Instead we wish to explore the potential of this techniq...

Synthetic aperture radar (SAR) multi-temporal interferometry (MTI) is one of the most promising satellite-based remote sensing techniques for fostering new opportunities in landslide hazard detection and assessment. MTI is attractive because it can provide very precise quantitative information on slow slope displacements of the ground surface over huge areas with limited vegetation cover. Although MTI is a mature technique, we are only beginning to realize the benefits of the high-resolution imagery that is currently acquired by the new generation radar satellites (e.g., COSMO-SkyMed, TerraSAR-X). In this work we demonstrate the potential of high resolution X-band MTI for wide-area detection of slope instability hazards even in tropical environments that are typically very harsh (eg. coherence loss) for differentialinterferometry applications. This is done by presenting an example from the island of Haiti, a tropical region characterized by dense and rapidly growing vegetation, as well as by significant climatic variability (two rainy seasons) with intense precipitation events. Despite the unfavorable setting, MTI processing of nearly 100 COSMO-SkyMed (CSK) mages (2011-2013) resulted in the identification of numerous radar targets even in some rural (inhabited) areas thanks to the high resolution (3 m) of CSK radar imagery, the adoption of a patch wise processing SPINUA approach and the presence of many man-made structures dispersed in heavily vegetated terrain. In particular, the density of the targets resulted suitable for the detection of some deep-seated and shallower landslides, as well as localized, very slow slope deformations. The interpretation and widespread exploitation of high resolution MTI data was facilitated by Google EarthTM tools with the associated high resolution optical imagery. Furthermore, our reconnaissance in situ checks confirmed that MTI results provided useful information on landslides and marginally stable slopes that can represent a

Context. Bolometric interferometry is a promising new technology with potential applications to the detection of B-mode polarization fluctuations of the cosmic microwave background (CMB). A bolometric interferometer will have to take advantage of the wide spectral detection band of its bolometers to be competitive with imaging experiments. A crucial concern is that interferometers are assumed to be significantly affected by a spoiling effect known as bandwidth smearing. Aims: We investigate how the bandwidth modifies the work principle of a bolometric interferometer and affects its sensitivity to the CMB angular power spectra. Methods: We obtain analytical expressions for the broadband visibilities measured by broadband heterodyne and bolometric interferometers. We investigate how the visibilities must be reconstructed in a broadband bolometric interferometer and show that this critically depends on hardware properties of the modulation phase shifters. If the phase shifters produce shifts that are constant with respect to frequency, the instrument works like its monochromatic version (the modulation matrix is not modified), while if they vary (linearly or otherwise) with respect to frequency, one has to perform a special reconstruction scheme, which allows the visibilities to be reconstructed in frequency subbands. Using an angular power spectrum estimator that accounts for the bandwidth, we finally calculate the sensitivity of a broadband bolometric interferometer. A numerical simulation is performed that confirms the analytical results. Results: We conclude that (i) broadband bolometric interferometers allow broadband visibilities to be reconstructed regardless of the type of phase shifters used and (ii) for dedicated B-mode bolometric interferometers, the sensitivity loss caused by bandwidth smearing is quite acceptable, even for wideband instruments (a factor of 2 loss for a typical 20% bandwidth experiment).

This is a compilation of my patents issued from 1997 to 2002, generally describing interferometer techniques that modify the coherence properties of broad-bandwidth light and other waves, with applications to Doppler velocimetry, range finding, imaging and spectroscopy. Patents are tedious to read in their original form. In an effort to improve their readability I have embedded the Figures throughout the manuscript, put the Figure captions underneath the Figures, and added section headings. Otherwise I have resisted the temptation to modify the words, though I found many places which could use healthy editing. There may be minor differences with the official versions issued by the US Patent and Trademark Office, particularly in the claims sections. In my shock physics work I measured the velocities of targets impacted by flyer plates by illuminating them with laser light and analyzing the reflected light with an interferometer. Small wavelength changes caused by the target motion (Doppler effect) were converted into fringe shifts by the interferometer. Lasers having long coherence lengths were required for the illumination. While lasers are certainly bright sources, and their collimated beams are convenient to work with, they are expensive. Particularly if one needs to illuminate a wide surface area, then large amounts of power are needed. Orders of magnitude more power per dollar can be obtained from a simple flashlamp, or for that matter, a 50 cent light bulb. Yet these inexpensive sources cannot practically be used for Doppler velocimetry because their coherence length is extremely short, i.e. their bandwidth is much too wide. Hence the motivation for patents 1 & 2 is a method (White Light Velocimetry) for allowing use of these powerful but incoherent lamps for interferometry. The coherence of the illumination is modified by passing it through a preparatory interferometer.

Two approximations, center-beam approximation and reference digital elevation model (DEM) approximation, are used in synthetic aperture radar (SAR) motion compensation procedures. They usually introduce residual motion compensation errors for airborne single-antenna SAR imaging and SARinterferometry. In this paper, we investigate the effects of residual uncompensated motion errors, which are caused by the above two approximations, on the performance of airborne along-track interferometric SAR (ATI-SAR). The residual uncompensated errors caused by center-beam approximation in the absence and in the presence of elevation errors are derived, respectively. Airborne simulation parameters are used to verify the correctness of the analysis and to show the impacts of residual uncompensated errors on the interferometric phase errors for ATI-SAR. It is shown that the interferometric phase errors caused by the center-beam approximation with an accurate DEM could be neglected, while the interferometric phase errors caused by the center-beam approximation with an inaccurate DEM cannot be neglected when the elevation errors exceed a threshold. This research provides theoretical bases for the error source analysis and signal processing of airborne ATI-SAR.

Designed especially for forest ecosystem studies, EcoSAR employs state-of-the-art digital beamforming technology to generate wide-swath, high-resolution imagery. EcoSARs dual antenna single-pass imaging capability eliminates temporal decorrelation from polarimetric and interferometric analysis, increasing the signal strength and simplifying models used to invert forest structure parameters. Antennae are physically separated by 25 meters providing single pass interferometry. In this mode the radar is most sensitive to topography. With 32 active transmit and receive channels, EcoSARs digital beamforming is an order of magnitude more versatile than the digital beamforming employed on the upcoming NISAR mission. EcoSARs long wavelength (P-band, 435 MHz, 69 cm) measurements can be used to simulate data products for ESAs future BIOMASS mission, allowing scientists to develop algorithms before the launch of the satellite. EcoSAR can also be deployed to collect much needed data where BIOMASS satellite wont be allowed to collect data (North America, Europe and Arctic), filling in the gaps to keep a watchful eye on the global carbon cycle. EcoSAR can play a vital role in monitoring, reporting and verification schemes of internationals programs such as UN-REDD (United Nations Reducing Emissions from Deforestation and Degradation) benefiting global society. EcoSAR was developed and flown with support from NASA Earth Sciences Technology Offices Instrument Incubator Program.

This work is focused on the infrastructure monitoring of areas which had experienced significant urbanization and therefore, also an increase of the exploitation of natural resources. Persistent Scatters Interferometry (PS-InSAR) and Small Baselines (SBAS) approaches are applied to three study areas for which large datasets of SAR images are available in ascending and descending modes to finally deploy deformation maps of different buildings and infrastructures. Valencia, Rome and South Sardinia areas have been selected for this study, having experienced an increase of the exploitation of natural resources in parallel with their urban expansion. Moreover, Rome is a very special case, where Cultural Heritage permeating the city and its surroundings would suggest the necessity of a tool for monitoring the stability of the different sites. This work wants to analyse the potential deformation that had occurred in these areas during the period 1992 to 2010, by applying Persistent Scatters Interferometry to ESA ERS SAR and Envisat ASAR data.

We are proposing to develop a miniaturized polarimetric L-band synthetic aperture radar (SAR) for repeat-pass differential interferometric measurements of deformation for rapidly deforming surfaces of geophysical interest such as volcanoes or earthquakes that is to be flown on a unmanned aerial vehicle (UAV) or minimally piloted vehicle (MPV). Upon surveying the capabilities and availabilities of such aircraft, the Proteus aircraft and the ALTAIR UAV appear to meet our criteria in terms of payload capabilities, flying altitude, and endurance. To support the repeat pass deformation capability it is necessary to control flight track capability of the aircraft to be within a specified 10 m tube with a goal of 1 m. This requires real-time GPS control of the autopilot to achieve these objectives that has not been demonstrated on these aircraft. Based on the Proteus and ALTAIR's altitude of 13.7 km (45,000 ft), we are designing a fully polarimetric L-band radar with 80 MHz bandwidth and a 16 km range swath. The radar will have an active electronic beam steering antenna to achieve a Doppler centroid stability that is necessary for repeat-pass interferometry. This paper presents some of the trade studies for the platform, instrument and the expected science.

Phase Estimation in Optical Interferometry covers the essentials of phase-stepping algorithms used in interferometry and pseudointerferometric techniques. It presents the basic concepts and mathematics needed for understanding the phase estimation methods in use today. The first four chapters focus on phase retrieval from image transforms using a single frame. The next several chapters examine the local environment of a fringe pattern, give a broad picture of the phase estimation approach based on local polynomial phase modeling, cover temporal high-resolution phase evaluation methods, and pre

Full Text Available This paper reviewed the result and processing of digital elevation model (DEM using L-Band ALOS PALSAR data and two-pass radar interferometry method in Bromo Mountain region. Synthetic Aperture Radar is an advanced technology that has been used to monitor deformation, land cover change, image detection and especially topographic information such as DEM. We used two scenes of SAR imageries to generate DEM extraction which assumed there is no deformation effect between two acquisitions. We could derive topographic information using phase difference by combining two single looks complex (SLC images called focusing process. The next steps were doing interferogram generation, phase unwrapping and geocoding. DEM-InSAR was compared to SRTM 90m that there were significant elevation differences between two DEMs such as smoothing surface and detail topographic. Particularly for hilly areas, DEM-InSAR showed better quality than SRTM 90 m where the elevation could have 25.94 m maximum gap. Although the processing involved adaptive filter to amplify the phase signal, we concluded that InSAR DEM result still had error noise because of signal wavelength, incidence angle, SAR image relationship, and only using ascending orbit direction.

This thesis introduces the idea that a simulated interferogram can be used as a reference for an interferometer. This new concept represents a paradigm shift from the conventional thinking, where a reference is the phase of a wavefront that traverses a known path. The simulated interferogram used as a reference is called a virtual reference. This thesis develops the theory of virtual reference interferometry and uses it for the characterization of chromatic dispersion in short length (virtual reference combines the advantages of these techniques so that it is both accurate and easy to operate. Chromatic dispersion measurements based on virtual reference interferometry have similar accuracy as the best conventional measurement techniques due to the ability to measure first and second order dispersion directly from the interference pattern. Unique capabilities of virtual reference interferometry are demonstrated, followed by a derivation of the operational constraints and system parameters. The technique is also applied to the characterization of few-mode fibers, a hot topic in telecommunications research where mode division multiplexing promises to expand network bandwidth. Also introduced is the theory of dispersive virtual reference interferometry, which can be used to overcome the bandwidth limitations associated with the measurement of near-zero dispersion-length optical components via compression of the interference pattern. Additionally, a method for utilizing the virtual reference interferometer in a low-coherence setup is introduced, enabling characterization in new wavelength ranges and further reducing the cost of characterization.

Experimental observations and measurements are the essential source of information necessary for correct development of mathematical models of real materials. Moire interferometry offers high sensitivity in full-field measurements of the in-plane displacements on the surface of the specimen. The (+OR-)45(DEGREES) method of moire interferometry increases the efficiency of a three-beam interferometer making its use outside of an optical laboratory more practical. Analysis of the (+OR-)45(DEGREES) method is provided. A concept of the vector representation of the fringe gradient is introduced and used in the analysis. Although existing systems require coherent light, the proposed system can use a relatively broad spectral bandwidth. Features that are related to the vibration sensitivity of such an instrument are investigated analytically. The basic concepts of an achromatic moire interferometry system are developed. Attachment of the critical elements of the system to the specimen solves the problem of relative rigid body motions, including vibrations, between the specimen and the virtual reference grating. Application of a laser diode light source reduces size, weight and cost of the interferometer making moire interferometry more practical for most materials testing laboratories. Laboratory tests confirmed the developed methods. This work enhances the probability of successful construction of a portable moire interferometer for measurements outside of the optical laboratory, in a mechanical testing or field environment.

AIPY collects together tools for radio astronomical interferometry. In addition to pure-python phasing, calibration, imaging, and deconvolution code, this package includes interfaces to MIRIAD (ascl:1106.007) and HEALPix (ascl:1107.018), and math/fitting routines from SciPy.

Polarimetric SAR-data of agricultural fields have been acquired by the Danish polarimetric L- and C-band SAR (EMISAR) during a number of missions at the Danish agricultural test site Foulum during 1995. The data are used to study the classification potential of polarimetric SAR data using...

This paper describes the experiment of the repeat pass interferometric SAR using Pi-SAR(L). The air-borne repeat-pass interferometric SAR is expected as an effective method to detect landslide or predict a volcano eruption. To obtain a high-quality interferometric image, it is necessary to make two flights on the same flight pass. In addition, since the antenna of the Pi-SAR(L) is secured to the aircraft, it is necessary to fly at the same drift angle to keep the observation direction same. We built a flight control system using an auto pilot which has been installed in the airplane. This navigation system measures position and altitude precisely with using a differential GPS, and the PC Navigator outputs a difference from the desired course to the auto pilot. Since the air density is thinner and the speed is higher than the landing situation, the gain of the control system is required to be adjusted during the repeat pass flight. The observation direction could be controlled to some extent by adjusting a drift angle with using a flight speed control. The repeat-pass flight was conducted in Japan for three days in late November. The flight was stable and the deviation was within a few meters for both horizontal and vertical direction even in the gusty condition. The SAR data were processed in time domain based on range Doppler algorism to make the complete motion compensation. Thus, the interferometric image processed after precise phase compensation is shown.

该文展示了世界上几个重要的先进混合双基SAR实验。混合双基模式是指发射端和接收端分别装载于不同类型的平台，例如星载/机载，机载/静止平台，星载/静止平台等。近年来相继有若干混合双基 SAR 实验成功完成，主要包括TerraSAR-X/PAMIR，PAMIR/静止平台，以及TerraSAR-X/静止平台。此外，在TerraSAR-X/静止平台的双基模式下还验证了多基线干涉 SAR (MB-InSAR)和数字波束形成(DBF)技术。值得强调的是，该文所展示的DBF实验结果属于世界上首次成功的基于在轨雷达卫星的DBF实验。%This study concentrates on the results of several advanced hybrid bistatic SAR experiments. The hybrid bistatic configuration applies to the case in which the transmitter and receiver are mounted on different types of platforms, e.g., spaceborne/airborne, airborne/stationary, spaceborne/stationary, and so on. Several hybrid bistatic SAR experiments have been performed successfully, i.e., TerraSAR-X/PAMIR, PAMIR/stationary, and TerraSAR-X/stationary. Furthermore, Multiple Baseline InterferometrySAR (MB-InSAR) and Digital Beam-Forming (DBF) technologies are validated in the TerraSAR-X/stationary configuration. Note that the DBF experiment results based on the spaceborne illuminator are discussed for the first time in SAR community. In addition, this paper emphasizes imaging geometry, image analysis, and focusing results.

Full Text Available Phase unwrapping is the most critical step in the processing of synthetic aperture radar interferometry. The phase obtained by SARinterferometry is wrapped over a range from $-\\pi$ to $\\pi$. Phase unwrapping must be performed to obtain the true phase. The least square approach attains the unwrapped phase by minimizing the difference between the discrete partial derivatives of the wrapped phase and the discrete partial derivatives of the unwrapped solution. The least square solution will result in discrete version of the Poisson's partial differential equation. Solving the discretized Poisson's equation with the classical method of Gauss-Seidel relaxation has extremely slow convergence. In this paper we have used Wavelet techniques which overcome this limitation by transforming low-frequency components of error into high frequency components which consequently can be removed quickly by using the Gauss-Seidel relaxation method. In Discrete Wavelet Transform (DWT two operators, decomposition (analysis and reconstruction (synthesis, are used. In the decomposition stage an image is separated into one low-frequency component (approximation and three high-frequency components (details. In the reconstruction stage, the image is reconstructed by synthesizing the approximated and detail components. We tested our algorithm on both simulated and real data and on both unweighted and weighted forms of discretized Poisson's equation. The experimental results show the effectiveness of the proposed method.

The application of Advanced Differential Interferometric Synthetic Aperture Radar (A-DINSAR) techniques has strongly emerged in the last two decades and became an important part in georelated fields. State-of-the-art A-DInSAR methods, such as Persistent Scatterer Interferometry (PSI) or the Small BASeline (SBAS) approach have demonstrated their usefulness in monitoring urban areas and single buildings, up to critical infrastructures. Combined with additional data from GPS networks or levelling, it could prove its large potential for an operational, cost-effective mapping of surface deformations. Given a reasonable amount of images, changes in surface deformation can be detected down to 1 mm/y. Compared to point-wise field measurements it offers a spatially consistent mapping approach from local to regional scales. In this review we want to provide a synopsis how A-DInSAR can be utilized in the framework of Nuclear Power Plant safety. Indeed, A-DInSAR is able to provide a detailed spatial analysis of slow movements occurring at NPP structures directly, as well as within the surrounding areas of the NPPs. Different phenomena of surface motion can be subject of such a monitoring. Natural causes, like active tectonics and terrain instability of slope which lead to landslides, as well as human-induced subsidence phenomena due to heavy construction or water pumping can be detected. We start by presenting techniques to determine the feasibility of the analysis for a given area and show its limitations. Then we propose a short insight into state-of-the-art studies where landslides, interseismic and human-induced deformation of the surface were mapped by A-DInSAR, to point out the relevance of a consequent analysis over an area of a NPP. Furthermore we present results of case studies from international projects (TERRAFIRMA) as well as preliminary results from the Krsko NPP in Slovenia. Finally, we provide a outlook into present and future trends concerning the use of freely

Campi Flegrei caldera, Italy, located along the Bay of Naples, has a long history of significant vertical deformation, with the most recent large uplift (>1.5m) occurring in 1983-1984. Each episode of uplift has been followed by a period of subsidence that decreases in rate with time and may be punctuated by brief episodes of lesser uplift. The large amplitude of the major uplifts that occur without volcanic activity, and the subsequent subsidence has been argued as evidence for hydrothermal amplification of any magmatic source. The later subsidence and its temporal decay have been argued as due to diffusion of the pressurized caldera fill material into the less porous surrounding country rock. We present satellite synthetic aperture radar (SAR) interferometry (InSAR) time series analysis of ERS and Envisat data from the European Space Agency, based on exploiting the Small Baseline Subset (SBAS) approach [Berardino et al., 2002]; this allows us to generate maps of relative surface deformation though time, beginning in 1992 through 2007, that are relevant to both ascending and descending satellite orbits. The general temporal behavior is one of subsidence punctuated by several lesser uplift episodes. The spatial pattern of deformation can be modeled through simple inflation/deflation sources in an elastic halfspace. Given the evidence to suggest that fluids may play a significant role in the temporal deformation of Campi Flegrei, rather than a purely magmatic or magma chamber-based interpretation, we model the temporal and spatial evolution of surface deformation as a hydrothermal fluid flow process. We use the TOUGH2-BIOT2 set of numerical codes [Preuss et al., 1999; Hsieh, 1996], which couple multi-phase (liquid-gas) and multi-component (H2O-CO2) fluid flow in a porous or fractured media with plane strain deformation and fluid flow in a linearly elastic porous medium. We explore parameters related to the depth and temporal history of fluid injection, fluid

On 24 August 2016, at 01:36 UTÇ the intra-Apennine extensional fault system of Central Italy released a destructive earthquake (MW 6.0). It produced widespread damage and fatalities, killing about 300 people and severely destroying the town of Amatrice and surrounding villages. After few hours, the Amatrice earthquake was followed by a significant aftershock (MW 5.5), which nucleated 15 km NW-ward. The epicentral area of the seismic sequence extends in the NNW-SSE direction, for a length of about 25-30 km. It is located at the hanging-wall of the WSW-dipping Vettore-Gorzano active extensional fault system. During the days following the main shock, a significant number of Synthetic Aperture Radar (SAR) data have been acquired from different passes and angles by the L-band ALOS-2, C-band Sentinel-1 and X-band COSMO-SkyMed satellites. This allowed us to map in a very short time the co-seismic ground displacements through the DifferentialSARInterferometry (DInSAR) technique, and also to evaluate their Vertical and East-West components with high details. The generated interferometric pattern is characterized by a double-eyed co-seismic shape that spans 20 km along the NNW-SSE direction and that well coincides with the epicentral areas. We modeled the seismic source that well fit the Mw 6.2 event. In particular, for this analysis, we separately applied an analytical Okada approach as well as a 3D Finite Element (FE) numerical modeling, the latter jointly exploiting DInSAR measurements and structural-geological data. The model obtained via the FE approach suggests that the Amatrice 2016 earthquake nucleated at 8 km deep along the intersection line between the Vettoretto-Redentore and the Northern Gorzano faults, and instantly geminated in two rupture patches that radiated with an approximate bilateral symmetry on the two fault planes. The two rupture patches covered differently shaped slip area, with aspect ratio that well recalls the shape of the interferometric lobes

A light weight SAR, suitable for use on short range tactical UAV, has been designed and built. The system consists of a fully digital receive array, and a very compact active transmit antenna. The approximate weight of the complete system is 6 kg, with power consumption below 75 W, depending on the

Precise topographical information has a very important role in geology, hydrology, natural resources survey and deformation monitoring. The extracting DEM technology based on synthetic aperture radar interferometry (InSAR) obtains the three-dimensional elevation of the target area through the phase information of the radar image data. The technology has large-scale, high-precision, all-weather features. By changing track in the location of the ground radar system up and down, it can form spatial baseline. Then we can achieve the DEM of the target area by acquiring image data from different angles. Three-dimensional laser scanning technology can quickly, efficiently and accurately obtain DEM of target area, which can verify the accuracy of DEM extracted by GBInSAR. But research on GBInSAR in extracting DEM of the target area is a little. For lack of theory and lower accuracy problems in extracting DEM based on GBInSAR now, this article conducted research and analysis on its principle deeply. The article extracted the DEM of the target area, combined with GBInSAR data. Then it compared the DEM obtained by GBInSAR with the DEM obtained by three-dimensional laser scan data and made statistical analysis and normal distribution test. The results showed the DEM obtained by GBInSAR was broadly consistent with the DEM obtained by three-dimensional laser scanning. And its accuracy is high. The difference of both DEM approximately obeys normal distribution. It indicated that extracting the DEM of target area based on GBInSAR is feasible and provided the foundation for the promotion and application of GBInSAR.

Typical synthetic aperture RADAR (SAR) imaging employs a co-located RADAR transmitter and receiver. Bistatic SAR imaging separates the transmitter and receiver locations. A bistatic SAR configuration allows for the transmitter and receiver(s) to be in a variety of geometric alignments. Sandia National Laboratories (SNL) / New Mexico proposed the deployment of a ground-based RADAR receiver. This RADAR receiver was coupled with the capability of digitizing and recording the signal collected. SNL proposed the possibility of creating an image of targets the illuminating SAR observes. This document describes the developed hardware, software, bistatic SAR configuration, and its deployment to test the concept of a ground-based bistatic SAR. In the proof-of-concept experiments herein, the RADAR transmitter will be a commercial SAR satellite and the RADAR receiver will be deployed at ground level, observing and capturing RADAR ground/targets illuminated by the satellite system.

Stepping acquired immunodeficiency syndrome (AIDS), severe acute respiratory syndrome (SARS) as another type of disease has been threatening mankind since late last year. Many scientists worldwide are making great efforts to study the etiology of this disease with different approaches. 13 species of SARS virus have been sequenced. However, most people still largely rely on the traditional methods with some disadvantages. In this work, we used Wolfram approach to study the relationship among SARS viruses and between SARS viruses and other types of viruses, the effect of variations on the whole genome and the advantages in the analysis of SARS based on this novel approach. As a result, the similarities between SARS viruses and other coronaviruses are not really higher than those between SARS viruses and non-coronaviruses.

The Louisiana coast is among the most productive coastal area in the US and home to the largest coastal wetland area in the nation. However, Louisiana coastal wetlands have been threatened by natural (sea-level rise) and human (infrastructure development) stresses; they constitute the major part of the wetland loss of the country. Monitoring Louisiana's coastal wetlands represent a large challenge for local and federal authorities due to the large amount of area and hostile environment. Insofar, optical remote sensing observations have been used to classify the wetlands, monitor land cover changes, and assess the wetland loss over time. However, optical data is insensitive to surface flow and, hence, unable to detect the width of the tidal zone and changes in this area over time. SARinterferometry can provide useful information and ease the monitoring task. Wetland InSAR is the only application of the InSAR technology that provides information of aquatic surface. It provides useful information on surface water level changes in both inland and coastal wetlands. In this study, we use InSAR and tide gauge observations to detect and compare surface water level changes in response to ocean tide propagation through the Louisiana coastal wetlands. Our data consist of ALOS PALSAR, Radarsat-1 and tide gauge information over the coast of Louisiana. In order to detect water level changes, we used mainly high coherence interferferograms with short temporal baselines (46-92 days for ALOS data and 24-48 days for Radarsat-1). Interferometric processing of the data provides details maps of water level changes in the coastal zone. Preliminary results indicate tidal changes of up 30 cm and that tidal flow is limited to 8-10 km from the open water. Our results also show that the tidal flow is disrupted by various man-made structures as, canals and roads. The high spatial resolution wetland InSAR observations can provide useful constraints for detailed coastal wetland flow models.

Full Text Available In this paper, we propose an advanced methodology to perform three-dimensional (3D Finite Element (FE modeling to investigate the kinematical evolution of a slow landslide phenomenon. Our approach benefits from the effective integration of the available geological, geotechnical and satellite datasets to perform an accurate simulation of the landslide process. More specifically, we fully exploit the capability of the advanced Differential Synthetic Aperture Radar Interferometry (DInSAR technique referred to as the Small BAseline Subset (SBAS approach to provide spatially dense surface displacement information. Subsequently, we analyze the physical behavior characterizing the observed landslide phenomenon by means of an inverse analysis based on an optimization procedure. We focus on the Ivancich landslide phenomenon, which affects a residential area outside the historical center of the town of Assisi (Central Italy. Thanks to the large amount of available information, we have selected this area as a representative case study highlighting the capability of advanced 3D FE modeling to perform effective risk analyses of slow landslide processes and accurate urban development planning. In particular, the FE modeling is constrained by using the data from 7 litho-stratigraphic cross-sections and 62 stratigraphic boreholes; and the optimization procedure is carried out using the SBAS-DInSAR retrieved results by processing 39 SAR images collected by the Cosmo-SkyMed (CSK constellation in the 2009–2012 time span. The achieved results allow us to explore the spatial and temporal evolution of the slow-moving phenomenon and via comparison with the geomorphological data, to derive a synoptic view of the kinematical activity of the urban area affected by the Ivancich landslide.

雷达差分干涉测量（D-InSAR）技术一种新兴的地表形变监测技术，具有精度高、监测范围广等特点。本文以甘肃平凉华亭煤矿为例研究该技术在矿区的应用，首先采用两轨法D-InSAR技术获取了矿区在2007-2010年的地表形变场，然后分析了InSAR地表形变场的特点。结果表明D-InSAR技术监测到的沉陷信息可以较为准确的反映矿区实际沉陷状况，可以作为一种获取大范围煤矿区的地表沉陷的有效方法。%Differential Synthetic Aperture Radar interferometry (D-InSAR) is a newly developed technique for monitoring ground deformation with some prominent advantages such as high accuracy and wide range monitoring. This paper obtained the deformation of the Huating mining area in 2007-2010 by the two-pass D-InSAR technology, and then analyzed the deformation field. The results showed that D-InSAR technology for monitoring mining collapse can accurately reflect the actual conditions, and can be as an effective way to get wide range of mining collapse.

Atom interferometry experiments are searching for evidence of chameleon scalar fields with ever-increasing precision. As experiments become more precise, so too must theoretical predictions. Previous work has made numerous approximations to simplify the calculation, which in general requires solving a three-dimensional nonlinear partial differential equation. This paper calculates the chameleonic force using a numerical relaxation scheme on a uniform grid. This technique is more general than previous work, which assumed spherical symmetry to reduce the partial differential equation to a one-dimensional ordinary differential equation. We examine the effects of approximations made in previous efforts on this subject and calculate the chameleonic force in a setup that closely mimics the recent experiment of Hamilton et al. Specifically, we simulate the vacuum chamber as a cylinder with dimensions matching those of the experiment, taking into account the backreaction of the source mass, its offset from the center, and the effects of the chamber walls. Remarkably, the acceleration on a test atomic particle is found to differ by only 20% from the approximate analytical treatment. These results allow us to place rigorous constraints on the parameter space of chameleon field theories, although ultimately the constraint we find is the same as the one we reported in Hamilton et al. because we had slightly underestimated the size of the vacuum chamber. This computational technique will continue to be useful as experiments become even more precise and will also be a valuable tool in optimizing future searches for chameleon fields and related theories.

Full Text Available Employing Polarimetric Interferometry Synthetic Aperture Radar (PolInSAR data to inverse forest parameters is a hot topic in the research field of PolInSAR. The typical forest parameter inversion algorithm is the three-stage inversion algorithm based on Random Volume over Ground (RVoG model. The errors of linear fitting and volume scattering correlation estimation are the major factors for parameter estimation accuracy. In this paper, straight line fitting employing the total least squares method is used to estimate the ground phase. Then, the Gamma function is applied as the line measure to adaptively estimate the volume scattering correlation. The improved three-stage inversion algorithm with PolInSAR is presented. The experiment result proves the forest parameters inversion result is accurate and reliable.

We describe our experiment MAGIA (misura accurata di G mediante interferometria atomica), in which we will use atom interferometry to perform a high precision measurement of the Newtonian gravitational constant G. Free-falling laser-cooled atoms in a vertical atomic fountain will be accelerated due to the gravitational potential of nearby source masses (SMs). Detecting this acceleration with techniques of Raman atom interferometry will enable us to assign a value to G. To suppress systematic effects we will implement a double-differential measurement. This includes launching two atom clouds in a gradiometer configuration and moving the SMs to different vertical positions. We briefly summarize the general idea of the MAGIA experiment and put it in the context of other high precision G-measurements. We present the current status of the experiment and report on analyses of the expected measurement accuracy.

Bolometric Interferometry (BI) is one of the most promising techniques for precise measurements of the Cosmic Microwave Background polarization. In this paper, we present the results of DIBO (Demonstrateur d'Interferometrie Bolometrique), a single-baseline demonstrator operating at 90 GHz, built to proof the validity of the BI concept applied to a millimeter-wave interferometer. This instrument has been characterized in the laboratory with a detector at room temperature and with a 4 K bolometer. This allowed us to measure interference patterns in a clean way, both (1) rotating the source and (2) varying with time the phase shift among the two interferometer's arms. Detailed modelisation has also been performed and validated with measurements.

radar interpretation and the assessment of the state of activity, intended as defined by Cruden and Varnes (1996). The information coming from the radar interpretation is the basis to evaluate the state of activity and the intensity of slow landslides. Two main situations can occur: the presence of PS within the already mapped landslides, and the presence of PS outside the previous mapped area resulting often in new landslides. The analysis of PSI data allowed to map 57 new landslides and gave information on 203 (39%) landslides mapped of the pre-existed PAI while the updated Landslide Inventory Map has 579 landslides totally: thus EO data did not give any additional information on 319 landslides of the pre-existing inventory map. Considering the 203 updated landslides, the modifications concern 155 phenomena while 48 are confirmed: the modifications are related to the boundary and/or the state of activity and the typology. All the new landslides added are considered active. It is worth noting that almost all the landslides where the state of activity is changed from dormant (or stabilized) to active involve urban areas and the road network where the reliability of radar benchmarks is higher. Radar satellite data were in particular very useful to map slow superficial movements named as "creep" that are widespread in the slopes around L'Aquila: the typical velocity is few centimeters per year which is perfectly suited to the capability of multi-interferometric techniques for ground deformation detection. References: Berardino, P., Costantini, M., Franceschetti, G., Iodice, A., Pietranera, L., Rizzo, V. (2003). use of differentialSARinterferometry in monitoring and modelling large slope instability at Maratea (Basilicata, Italy). Engineering Geology, 68 (1-2), 31 - 51. Casagli N., Colombo D., Ferretti A., Guerri L., Righini G. (2008)- Case Study on Local Landslide Risk Management During Crisis by Means of Remote Sensing Data. Proceedings of the First World Landslide

Using DInSAR as a tool to detect unstable terrain areas in an Andes region in Ecuador (South America) 1. INTRODUCTION Monitoring landslides is a mandatory task in charge on the National Institute of Geological Research (INIGEMM) in Ecuador. It is a small country, supposedly will be faster doing monitoring, but what about its geographic characteristics? Lamentably, due to human and financial resources is not possible to put monitoring systems in unstable terrain areas. However, getting ALOS data to accessible price and using open source software to produce interferograms, could be a first step to know steep areas covered by vegetation and where mass movements are not visible. Under this statement, this study is part of the final research in a master study developed at CONAE during 2009-2011, with oral defense in August 2013. As a new technique used in Ecuador, the study processed radar data from ERS-1/2 and ALOS sensor PALSAR for getting differential interferograms, using ROI_PAC software. Stacking DInSAR is applied to get an average of displacement that indicates uplift and subsidence in the whole radar scene that covers two provinces in the Andes region. 2. PROBLEM Mass movements are present in the whole territory, independently of their magnitude and dynamic (slow or fast), they are a latent threat in winter season specially. There are registers of monitoring, such as two GPS's campaigns and artisanal extensometers, which are used to contrast with DInSAR results. However, the campaigns are shorter and extensometers are no trust on all. 3. METHODOLOGY Methodology has four phases of development: (1) Pre-processing of RAW data; (2) Processing of RAW data in ROI_PAC; (3) Post-processing for getting interferograms in units of cm per year; (4) Analysis of the results and comparison with ground truth. Sandwell & Price (1998) proposed Stacking technique to increase the fringes and decrease errors due to the atmosphere, to average several interferograms. L band penetrates

Digital Elevation Model (DEM) derived from survey data is accurate but it is very expensive and time-consuming. In recent years, remote sensing techniques including Synthetic Apenture Radar Interferometry (InSAR) had been developed as a powerful method to derive high precision DEM, especially in mountainous or deep forest areas. The purpose of this paper is to illustrate the principle of InSAR and show the result of a case study in Gejiu city, Yunnan province, China. The accuracy of DEM derived from InSAR (abbreviation as InSAR-DEM) is also evaluated by comparing it with DEM generated from topographic map at the scale of 1:50000 (abbreviation as TOP-DEM). The result shows that: (1)The general precision of the whole selected area acquired by subtracting InSAR-DEM from TOP-DEM is that the maximum, the minimum, the RMSE, and the mean of difference of the two DEMs are 203m, -188m, 26.9m and 5.7m respectively. (2)The topographic trend represented by the two DEMs is coincident, even though TOP-DEM is finer than InSAR-DEM, especial at the valley. (3) Contour maps with the interval of 100m and 50m converted from InSAR-DEM and TOP-DEM respectively show accordant relief trend. Contour from TOP-DEM is smoother than that of from InSAR-DEM, while Contour from InSAR-DEM has more islands than that of from TOP-DEM.(4) Coherence has great influence on the precision of InSAR-DEM, the precision of low-coherence area approaches 100 m while that of high-coherence area can up to m level. (5) The relief trend of 6 profiles represented by InSAR-DEM and TOP-DEM is accordant with tiny difference in partial minutiae. InSAR-DEM displays hypsographies at relative flat areas including surface of water, which reflects the influence of flat earth on InSAR to a certain extent.

Synthetic Aperture Radar (SAR) is critical for remote sensing. It works day and night, in good weather or bad. Bistatic SAR is a new kind of SAR system, where the transmitter and receiver are placed on two separate platforms. Bistatic SAR is one of the most important trends in SAR development, as the technology renders SAR more flexible and safer when used in military environments. Imaging is one of the most difficult and important aspects of bistatic SAR data processing. Although traditional SAR signal processing is fully developed, bistatic SAR has a more complex system structure, so sign

In this work techniques for visualizing phase and opaque objects by ruby laser interferometry are introduced. A leakage flow as a phase object is studied by holographic interferometry and the intensity distribution of the interferograms presenting the leakage flow are computer-simulated. A qualitative and quantitative analysis of the leakage flow is made. The analysis is based on the experimental and theoretical results presented in this work. The holographic setup and the double pass method for visualizing leakage flow are explained. A vibrating iron plate is the opaque object. Transient impact waves are generated by a pistol bullet on the iron plate and visualized by holographic interferometry. An apparatus with the capability of detecting and calculating the delays necessary for laser triggering is introduced. A time series of interferograms presenting elastic wave formation in an iron plate is shown. A computer-simulation of the intensity distributions of these interferograms is made. An analysis based on the computer-simulation and the experimental data of the transient elastic wave is carried out and the results are presented. (author)

SAR++ is a technology program aiming at developing know-how and technology needed to design the next generation civilian SAR systems. Technology has reached a state, which allows major parts of the digital subsystem to be built using custom-off-the-shelf (COTS) components. A design goal is to des......SAR++ is a technology program aiming at developing know-how and technology needed to design the next generation civilian SAR systems. Technology has reached a state, which allows major parts of the digital subsystem to be built using custom-off-the-shelf (COTS) components. A design goal...... is to design a modular, scalable and reconfigurable SAR system using such components, in order to ensure maximum flexibility for the users of the actual system and for future system updates. Having these aspects in mind the SAR++ system is presented with focus on the digital subsystem architecture...... and the analog to digital interface....

A comprehensive analysis of the earthquake cycle is a key issue for the definition of the hazard in seismic areas. Advanced SARInterferometry (A-InSAR) techniques have today a key role in Earth Sciences thanks to the capability to detect and measure slow surface movements along wide areas, and to follow the evolution of signal along a certain time periods. A-InSAR techniques have been applied to large datasets of SAR images spanning long time intervals and, together with in-situ surveys and ground measurements, can provide suitable information about the causes of post seismic (deformation rebound or residual strain release) and interseismic (seismic, creep) movements. In the framework of FP7 MARSITE (Marmara Supersite) project we have investigated the Western sector of North Anatolian Fault System (NAFS) from Istanbul toward Duzce area. From West toward the Marmara Sea region (Mudurnu/Akyaz) the NAFS begins to lose its single fault line character and splays into a complex fault system. The main Marmara Fault is argued to be a very young structure and exhibits typical characteristics of a major strike slip fault. In 1999 the August 17th Izmit earthquake was followed few months later by the Duzce mainshock. We compare the A-InSAR results to permanent GPS stations installed in the region after the Izmit/Duzce earthquakes. These observations allow studying the post-seismic deformation of the 1999 Izmit/Düzce earthquake. We investigate the response of the eastern Marmara Fault to the quasi-static loading caused by Izmit/Düzce earthquakes. Overlapped post-seismic processes of fault creep (or afterslip) and viscoelastic relaxation of the lower crust and the upper mantle were investigated. We firstly estimated the viscoelastic relaxation effect using well covered long-term GPS data. This relaxation effect was subtracted from the InSAR data and the remaining InSAR data was inverted to identify localized slip variation along the MMF. Our inversion results imply that part

利用欧空局ENVISAT ASAR雷达数据,获取了SAR影像的干涉条纹并结合SRTM DEM数据,分别采用了二路差分和三路差分对武安市下团城村铁矿区域地表沉降进行监测,获得了区域内的最大沉降值和沉降带分布情况,初步探索了无目标、无时域、大范围、高精度地对地表进行沉降监测的方法,得出了影响最终结果精度的主要因素.%The interference stripes of SAR image was obtained by using radar data of the European Space Agency ENVISAT ASAR. Through monitoring land subsidence in Xiatuancheng Iron Mine in Wu'an city by means of two-pass and three-pass differentialinterferometry, the maximum subsidence value and the distribution of subsidence zone were determined,with combination of the SRTM DEM data. And the technology of large scale and high accurate land snbsidence monitoring without target and time domain was preliminarily explored. Then the main factors of affecting the accuracy of final results were got.

We used multi-temporal European Remote Sensing Satellites 1 and 2 (ERS-1/2), Environment Satellite (ENVISAT), and Canadian RADARSAT-1 Synthetic Aperture Radar (SAR) images for ecological, hydrological, and geological studies of the Southeastern Louisiana coastal flood zone. First, we present a distinctive correlation among the seasonal changes in SAR backscatter, interferometric coherence, and land cover types with the associated normalized difference vegetation indices. Second, we demonstrate the use of C-band SAR images to measure changes in the water-level beneath moderately dense swamp forests, at a vertical accuracy and spatial resolution that is not possible with the current gauge-based measurements. Finally, we apply the conventional SARinterferometry (InSAR) and the Permanent Scatterer InSAR techniques to map land surface subsidence in New Orleans and the surrounding area; the comparison of measured subsidence patterns shows certain discrepancies that are probably due to atmospheric delays in this humid area. Our study demonstrates the importance of SAR data for understanding this coastal flood zone and the associated ecological, hydrological, and geological processes.

Full Text Available Airborne differential synthetic aperture radar interferometry (D-InSAR is a kind of potential technology to survey the surface deformation. In this paper, the errors of two usually used modes of this technology, namely, two-pass and three-pass approaches, are compared and analyzed. In the analysis, all the errors are decomposed and sorted according to the principle of independence, and the coupling between motion error and other errors is considered. Based on the analysis, analytical expressions are derived for the deformation measurement errors in the two modes. The results demonstrate that when the amplitude of the motion error is small, the three-pass approach can reduce the requirement on the precision of the external topography data, so it distinctly outperforms the two-pass approach; when the amplitude of the motion error is large, high-precision topography data are needed in the three-pass approach, and as a result, its advantage over the two-pass approach is not distinct any more.

We introduce seismic interferometry of passive data by multidimensional deconvolution (MDD) as an alternative to the crosscorrelation method. Interferometry by MDD has the potential to correct for the effects of source irregularity, assuming the first arrival can be separated from the full response.

Recent advances at JPL in experimentation and design for LISA interferometry include the demonstration of Time Delay Interferometry using electronically separated end stations, a new arm-locking design with improved gain and stability, and progress in flight readiness of digital and analog electronics for phase measurements.

Recent advances at JPL in experimentation and design for LISA interferometry include the demonstration of time delay interferometry using electronically separated end stations, a new arm-locking design with improved gain and stability, and progress in flight readiness of digital and analog electronics for phase measurements.

in substantial errors (up to 20%) also on the south-north component of horizontal velocities derived by satellite synthetic aperture radar interferometry (InSAR) measurements. In many glacier environments, the steady-state vertical velocity component required to balance the annual ablation rate is 5-10 m a(-1...... tracks with airborne ice-sounding radar measurement of ice thickness. The results are compared to InSAR velocities previously derived by using the SPF assumption, and to velocities obtained by in situ global positioning system (GPS) measurements. The velocities derived by using the MC principle...

The CUbesat Radio Interferometry Experiment (CURIE) is a proposed two-element radio interferometer, based on proven and developed digital radio receivers and designed to fit within a Cubesat platform. CURIE will launch as a 6U Cubesat and then separate into two 3U Cubesats once in orbit. CURIE measures radio waves from 0.1-19MHz, which must be measured from space, as those frequencies fall below the cutoff imposed by Earth's ionosphere. The principal science objective for CURIE is to use radio interferometry to study radio burst emissions from solar eruptive events such as flares and coronal mass ejections (CMEs) in the inner heliosphere, providing observations important for our understanding of the heliospheric space weather environment. The influence of space weather can be felt at Earth and other planets, as radiation levels increase and lead to auroral activity and geomagnetic effects. CURIE will be able to determine the location and size of radio burst source regions and then to track their movement outward from the Sun. In addition to the primary objective CURIE will measure the gradients of the local ionospheric density and electron temperature on the spatial scale of a few kilometers, as well as create an improved map of the radio sky at these unexplored frequencies. A space based radio interferometry observatory has long been envisioned, in orbit around the Earth or the Moon, or on the far side of the Moon. Beyond its important science objectives, CURIE will prove that the concept of a dedicated space-based interferometer can be realized by using relatively cheap Cubesats. CURIE will therefore not only provide new important science results but also serve as a pathfinder in the development of new space-based radio observation techniques for helio- and astro-physics.

Only book on Permanent Scatterer technique of radar interferometryExplains the Permanent Scatterer technique in detail, possible pitfalls, and details a newly developed stochastic model and estimator algorithm to cope with possible problems for the application of the PS techniqueThe use of Permanent Scatterer allows very precise measurements of the displacement of hundreds of points per square kilometerDescribes the only technique currently able to perform displacement measurements in the past, utilizing the ERS satellite data archive using data acquired from 1992-prese

This paper is devoted to the contribution of Yuri Ostrovsky to holographic interferometry, one of the fundamental scientific and practical applications of holography. The title of this paper is the same as the title of his doctoral thesis that he defended in 1974, and, as it seems to me, reflects most of the specific features of the majority of his scientific publications, viz., an inseparable link of the methods developed by him with the results obtained with the help of these methods in a wide range of investigations of physical processes and phenomena.

The present use of moire interferometry for low amplitude vibration and analysis demonstrates the possibility of obtaining out-of-plane displacement contours whose sensitivity is comparable to that of holographic methods. A major advantage of the present system, is the obviation of prior knowledge of resonant frequencies, as called for in time-average holography. The experimental apparatus employed encompasses a laser beam, a parabolic mirror, a high frequency (600 line/mm) grating, and a camera, in addition to the test model.

We present a formal comparison of the performance of algorithms used for synthesis imaging with optical/infrared long-baseline interferometers. Six different algorithms are evaluated based on their performance with simulated test data. Each set of test data is formated in the interferometry Data Exchange Standard and is designed to simulate a specific problem relevant to long-baseline imaging. The data are calibrated power spectra and bispectra measured with a ctitious array, intended to be typical of existing imaging interferometers. The strengths and limitations of each algorithm are discussed.

In recent years, the method of Corner Reflectors Differential Interferometric Synthetic Aperture Radar (CRDInSAR) was proposed for overcoming the limitations of decorrelations of the conventional differential interferometric synthetic aperture radar (DInSAR) technique. In general, the corner reflector has very high RCS (Radar Cross Section) for a small size, and the maximum RCS occurs when it points directly along the boresight of the SAR antenna. The beam width of a trihedral corner reflector is rather broad (having a 3dB beam width of 40° in both elevation and azimuth), so it is fairly tolerant to installation errors. It can be made available as artificial PS (Permanent Scatterers) points by installing them on a study area due to the stable amplitude and phase performance. However, some errors of CRDInSAR system will still affect the results of measurement. In this paper, the factors influence the accuracy of CRDInSAR are discussed, which include the errors of baseline and its angle, look angle and height of corner reflector respectively.

Subsidence hazard and risk within the USCB are usually connected with the deep coal mining. In such cases, the surface becomes pitted with numerous collapse cavities or basins which depth may even reach tens of meters. The subsidence is particularly dangerous because of causing severe damage to gas and water pipelines, electric cables, and to sewage disposal systems. The PGI has performed various analysis of InSAR data in this area, including all three SAR bands (X, C and L) processed by DInSAR, PSInSAR and SqueeSAR techniques. These analyses of both conventional and advanced DInSAR approaches have proven to be effective to detect the extent and the magnitude of mining subsidence impact on urban areas. In this study an analysis of two series of subsequent differential interferograms obtained in the DInSAR technique are presented. SAR scenes are covering two periods and were acquired by two different satellites: ALOS-P ALSAR data from 22/02/2007- 27/05/2008 and TerraSAR-X data from 05/07/2011-21/06/2012. The analysis included determination of the direction and development of subsidence movement in relation to the mining front and statistic comparison between range and value of maximum subsidence detected for each mining area. Detailed studies were performed for Bobrek-Centrum mining area. They included comparison of mining fronts and location of the extracted coal seams with the observed subsidence on ALOS-P ALSAR InSAR interferograms. The data can help in estimation not only the range of the subsidence events, but also its value, direction of changes and character of the motion.

To demonstrate the feasibility of orbital remote sensing for global ocean observations, NASA launched Seasat on June 27th, 1978. Being the first space borne SAR mission, Seasat produced the most detailed SAR images of Earth from space ever seen to that point in time. While much of the data collected in the USA was processed optically, a mere 150 scenes had been digitally processed by March 1980. In fact, only an estimated 3% of Seasat data was ever digitally processed. Thus, for over three decades, the majority of the SAR data from this historic mission has been dormant, virtually unavailable to scientists in the 21st century. Over the last year, researchers at the Alaska Satellite Facility (ASF) Distributed Active Archive Center (DAAC) have processed the Seasat SAR archives into imagery products. A telemetry decoding system was created and the data were filtered into readily processable signal files. Due to nearly 35 years of bit rot, the bit error rate (BER) for the ASF DAAC Seasat archives was on the order of 1 out of 100 to 1 out of 100,000. This extremely high BER initially seemed to make much of the data undecodable - because the minor frame numbers are just 7 bits and no range line numbers exist in the telemetry even the 'simple' tasks of tracking the minor frame number or locating the start of each range line proved difficult. Eventually, using 5 frame numbers in sequence and a handful of heuristics, the data were successfully decoded into full range lines. Concurrently, all metadata were stored into external files. Recovery of this metadata was also problematic, the BER making the information highly suspect and, initially at least, unusable in any sort of automated fashion. Because of the BER, all of the single bit metadata fields proved unreliable. Even fields that should be constant for a data take (e.g. receiving station, day of the year) showed high variability, each requiring a median filter to be usable. The most challenging, however, were the

Earth surface displacement measurement from space using Synthetic Aperture Radar (SAR) imagery is an interesting alternative to SARinterferometry (InSAR). The advantages are that 2D information can be retrieved (InSAR only 1D), absolute displacements can be retrieved (no reference point required) and it is very robust (phase unwrapping not required). On the other hand, the accuracy is limited by the pixel resolution, the object contrast, the orbit accuracy, by wave propagation distortion and by geodetic effects. Therefore the accuracy was more in the meter / decimeter level in the past, compared to millimeter accuracy of InSAR. During the recent years our team established a test and validation site at the geodetic observatory Wettzell, Germany and developed compensation methods to reduce the overall error of absolute range measurements from decimeters to only one centimeter. The methods include correction of dry and wet atmospheric delays, ionospheric corrections, solid earth tides, continental drift, atmospheric pressure loading and ocean tidal loading. For more one year a radar reflector was monitored and each image evaluated. Our presentation gives and overview of methods and achieved results. Futhermore, examples of real world applications and an outlook on more applications is given such as phase unwrapping augmentation.

This paper provides analytical principles to relate the signature of a moving target to parameters in a SAR system. Our objective is to establish analytical tools that could predict the shift and smearing of a moving target in a subaperture SAR image. Hence, a user could identify the system parameters such as the coherent processing interval for a subaperture that is suitable to localize the signature of a moving target for detection, tracking and geolocating the moving target. The paper begins by outlining two well-known SAR data collection methods to detect moving targets. One uses a scanning beam in the azimuth domain with a relatively high PRF to separate the moving targets and the stationary background (clutter); this is also known as Doppler Beam Sharpening. The other scheme uses two receivers along the track to null the clutter and, thus, provide GMTI. We also present results on implementing our SAR-GMTI analytical principles for the anticipated shift and smearing of a moving target in a simulated code. The code would provide a tool for the user to change the SAR system and moving target parameters, and predict the properties of a moving target signature in a subaperture SAR image for a scene that is composed of both stationary and moving targets. Hence, the SAR simulation and imaging code could be used to demonstrate the validity and accuracy of the above analytical principles to predict the properties of a moving target signature in a subaperture SAR image.

Urban geological hazards involving ground instability can be costly, dangerous, and affect many people, yet there is little information about the extent or distribution of geohazards within Europe's urban areas. A reason for this is the impracticality of measuring ground instability associated with the many geohazard processes that are often hidden beneath buildings and are imperceptible to conventional geological survey detection techniques. Satellite radar interferometry, or InSAR, offers a remote sensing technique to map mm-scale ground deformation over wide areas given an archive of suitable multi-temporal data. The EC FP7 Space project named PanGeo (2011-2014), used InSAR to map areas of unstable ground in 52 of Europe's cities, representing ∼15% of the EU population. In partnership with Europe's national geological surveys, the PanGeo project developed a standardised geohazard-mapping methodology and recorded 1286 instances of 19 types of geohazard covering 18,000 km2. Presented here is an analysis of the results of the PanGeo-project output data, which provides insights into the distribution of European urban geohazards, their frequency and probability of occurrence. Merging PanGeo data with Eurostat's GeoStat data provides a systematic estimate of population exposures. Satellite radar interferometry is shown to be as a valuable tool for the systematic detection and mapping of urban geohazard phenomena.

Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. This paper presents two possible implementations of a dual 85Rb-87Rb atom interferometer to perform differential gravity measurements in space, with the primary goal to test the Weak Equivalence Principle. The proposed scheme is in the framework of two projects of the European Space Agency, namely Q-WEP and STE-QUEST. The paper describes the baseline experimental configuration, and discusses the technology readiness, noise and error budget for the two proposed experiments.

Traditional speckle fringe patterns by electronic speckle pattern interferometry (ESPI) are inherently noisy and of limited visibility, so denoising is the key problem in ESPI. We present the variational denoising method for ESPI. This method transforms the image denosing to minimizing an appropriate penalized energy function and solving a partial differential equation. We test the proposed method on computer-simulated and experimental speckle correlation fringes, respectively. The results show that this technique is capable of significantly improving the quality of fringe patterns. It works well as a pre-processing for the fringe patterns by ESPI.

Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. This paper presents two possible implementations of a dual {sup 85}Rb-{sup 87}Rb atom interferometer to perform differential gravity measurements in space, with the primary goal to test the Weak Equivalence Principle. The proposed scheme is in the framework of two projects of the European Space Agency, namely Q-WEP and STE-QUEST. The paper describes the baseline experimental configuration, and discusses the technology readiness, noise and error budget for the two proposed experiments.

Orbits of 55 visual binary stars are computed using recent speckle interferometry data from the SOAR telescope: 33 first-time orbits and 22 revisions of previous orbit calculations. The orbital periods range from 1.4 to 370 years, the quality of orbits ranges from definitive to preliminary and tentative. Most binaries consist of low-mass dwarfs and have short periods (median period 31 years). The dynamical parallaxes and masses are evaluated and compared to the Hipparcos parallaxes. Using differential speckle photometry, binary components are placed on the color-magnitude diagram.

A spectral-domain differential interference contrast (SD-DIC) microscopy system is presented for quantitative imaging of both reflective and transparent samples. The spectral-domain interferometry, combined with the common-path DIC geometry, provides a shot noise-limited sensitivity of 14.3pm in optical pathlength gradient measurement. The optical resolution of the system was characterized using images of a USAF resolution target. Fused silica microspheres were imaged to demonstrate the reconstruction of two-dimensional optical pathlength topography from measured gradient fields. The exquisite sensitivity of the system showed potential in quantitative imaging of sub-diffraction limit objects such as gold nanoparticles.

While typical SAR imaging employs a co-located (monostatic) RADAR transmitter and receiver, bistatic SAR imaging separates the transmitter and receiver locations. The transmitter and receiver geometry determines if the scattered signal is back scatter, forward scatter, or side scatter. The monostatic SAR image is backscatter. Therefore, depending on the transmitter/receiver collection geometry, the captured imagery may be quite different that that sensed at the monostatic SAR. This document presents imagery and image products formed from captured signals during the validation stage of the bistatic SAR research. Image quality and image characteristics are discussed first. Then image products such as two-color multi-view (2CMV) and coherent change detection (CCD) are presented.

Beijing has been severely affected by SARS, and SARS-associated coronavirus has been confirmed as its cause. However, clinical and experimental evidence implicates the possibility of co-infection. In this report, reovirus was isolated from throat swabs of SARS patients, including the first case in Beijing andher mother. Identification with the electron microscopy revealed the characteristic features of reovirus. 24 of 38 samples from other SARS cases were found to have serologic responses to the reovirus. Primers designed for reovirus have amplified several fragments of DNA, one of which was sequenced (S2 gene fragment), which indicates it as a unique reovirus (orthoreovirus). Preliminary animal experiment showed that inoculation of the reovirus in mice caused death with atypical pneumonia. Nevertheless, the association of reovirus with SARS outbreak requires to be further investigated.

The application of Synthetic Aperture Radar (SAR) techniques to classical radar altimetry offers the potential for greatly improved Earth surface mapping. This paper provides an overview of the progress of SAMOSA, Development of SAR Altimetry Studies and Applications over Ocean, Coastal zones and Inland waters, an on-going ESA-funded project. The main objective of SAMOSA is to better quantify the improvement of SAR altimetry over conventional altimetry on water surfaces. More specifically, one of the tasks focuses on the reduction of SAR mode data to pulse-limited altimeter data, and a theoretical modelling to characterize the expected gain between high Pulse Repetition Frequency (PRF) reduced SAR mode data and low PRF classical Low-Resolution Mode (LRM) data. To this end, theoretical modelling using the Cramer-Rao bound (CRB) will be used and the results will be compared to previous theoretical estimates [7], using an analysis akin to that in [8].

The Bibliography of Spatial Interferometry in Optical Astronomy is a guide to the published literature in applications of spatial interferometry techniques to astronomical observations, theory and instrumentation at visible and infrared wavelengths. The key words spatial and optical define the scope of this discipline, distinguishing it from spatial interferometry at radio wavelengths, interferometry in the frequency domain applied to spectroscopy, or more general electro-optics theoretical and laboratory research. The main bibliography is a listing of all technical articles published in the international scientific literature and presented at the major international meetings and workshops attended by the spatial interferometry community. Section B summarizes publications dealing with the basic theoretical concepts and algorithms proposed and applied to optical spatial interferometry and imaging through a turbulent atmosphere. The section on experimental techniques is divided into twelve categories, representing the most clearly identified major areas of experimental research work. Section D, Observations, identifies publications dealing specifically with observations of astronomical sources, in which optical spatial interferometry techniques have been applied.

卫星成像的基线、视角、基线倾斜角、斜距、卫星距离地面径向距离以及地面分辨率等因素严重影响着合成孔径雷达差分干涉测量监测地面形变的能力和形变监测结果的精度.本文在分析四轨法D-InSAR基本原理和数据处理流程基础上,详细给出了相位测量误差对形变测量精度影响的定量关系式;分析讨论了基线长度误差、基线倾斜角误差、斜距误差、卫星高度误差和地形因素误差对形变测量精度的影响.从而在定量分析方面得出了这些误差对四轨法D-InSAR形变测量精度影响的结论.%Differentialinterferometry synthetic aperture radar(D-InSAR)is further development of InSAR,and four-pass D-InSAR is one type of data processing by this method.Because many uncertain factors affect the accuracy of data processing of four-pass D-InSAR,it is not applied widely in the monitoring of land deformation.However,four-pass D-InSAR does not require an external digital elevation model and has the advantage of a possible guarantee of the accuracy of monitoring deformation.The baseline,visual angle,baseline tilt angle,slope range,satellite orbit height,ground resolution,and other satellite imaging factors significantly affect the capability and accuracy of D-InSAR measurement in monitoring land subsidence; satellite orbit error is the main factor affecting the accuracy of deformation measurement when using four-pass D-InSAR.The difference in satellite orbit and radar frequency is generated by various sensors of satellites acquiring radar images,which could also significantly affect deformation measurement with this method.The system and speckle noise,loss of pixel registration,visual number,and temporal and baseline decorrelation are the main sources of phase measurement error and significantly affect each pixel of images from the coherent radar,for which the phase error affecting the accuracy of deformation measurement when using four-pass D-InSAR

Experimental observations and measurements are the sources of information essential for correct development of mathematical models of real structural materials. Moiré interferometry offers high sensitivity in full-field measurements of in-plane displacements on the surface of a specimen. Although it is a powerful method in experimental stress analysis, it has some shortcomings. One is that existing systems require highly coherent light. The only sufficient source of light for this application is a long cavity laser, which is relatively expensive and at best cumbersome. Another shortcoming is that measurements must be performed in a vibration-free environment, such as that found on a holographic table. These requirements limit the use of existing moiré interferometers to a holographic laboratory. In this paper a modified concept of compensation is presented, which permits the use of a chromatic source of light in a compact moiré system. The compensator provides order in the angles of incident light for each separate wavelength, so that the virtual reference grating created by each wavelength in a continuous spectrum is identical in frequency and spatial position. The result is a virtual reference grating that behaves exactly like that created in coherent light. With this development the use of a laser diode, which is a non-coherent light source of tiny dimensions, becomes practical. The special configuration of the optics that create the virtual grating allows its synchronization with the specimen grating and leads to an interferometer design that is relatively insensitive to the vibrations found in a mechanical testing laboratory. Sensitivity to relative motion is analyzed theoretically. This development provides the oppurtunity to apply moiré interferometry to solid mechanics problems that cannot be studied in an optics laboratory. Experimental verification of the optical concepts is provided. A compact moiré interferometer based on the presented idea was

Full Text Available Changes in soil moisture between two radar acquisitions can impact the observed coherence in differentialinterferometry: both coherence magnitude |Υ| and phase Φ are affected. The influence on the latter potentially biases the estimation of deformations. These effects have been found to be variable in magnitude and sign, as well as dependent on polarization, as opposed to predictions by existing models. Such diversity can be explained when the soil is modelled as a half-space with spatially varying dielectric properties and a rough interface. The first-order perturbative solution achieves–upon calibration with airborne L band data–median correlations ρ at HH polarization of 0.77 for the phase Φ, of 0.50 for |Υ|, and for the phase triplets ≡ of 0.56. The predictions are sensitive to the choice of dielectric mixing model, in particular the absorptive properties; the differences between the mixing models are found to be partially compensatable by varying the relative importance of surface and volume scattering. However, for half of the agricultural fields the Hallikainen mixing model cannot reproduce the observed sensitivities of the phase to soil moisture. In addition, the first-order expansion does not predict any impact on the HV coherence, which is however empirically found to display similar sensitivities to soil moisture as the co-pol channels HH and VV. These results indicate that the first-order solution, while not able to reproduce all observed phenomena, can capture some of the more salient patterns of the effect of soil moisture changes on the HH and VV DInSAR signals. Hence it may prove useful in separating the deformations from the moisture signals, thus yielding improved displacement estimates or new ways for inferring soil moisture.

Swelling soils may induce small surface displacements under various climatic conditions, that may affect individual buildings. The aim of this work, funded by MAIF foundation (Insurance foundation), is to monitor those small seasonal-dependant displacements through DINSAR and persistent scatterer interferometric methods. The eastern paris basin is locally composed of outcropping Marne de Pantin and Argiles Vertes particularily sensible to swelling phenomena observed during for instance the last dryness event of 2003. Radar differentialinterferometry (DINSAR) method which enables one to map surface displacements from two radar images acquired on a specific area gives rather poor results and is not that efficient in the eastern Paris Basin highly due to the temporal decorrelation. On the contrary, interesting results are obtained with Persistent Scatterer Interferometry (PSI) which reveal precisely the surface displacements, continuous in time. This new application of interferometry presents high potential to better understand the swelling soil natural hazards and the induced geologic processes.

A principal measure of Synthetic Aperture Radar (SAR) image quality is the manifestation in the SAR image of a spatial impulse, that is, the SAR's Impulse Response (IPR). IPR requirements direct certain design decisions in a SAR. Anomalies in the IPR can point to specific anomalous behavior in the radar's hardware and/or software.

Augustine volcano is an active stratovolcano located at the southwest of Anchorage, Alaska. Augustine volcano had experienced seven significantly explosive eruptions in 1812, 1883, 1908, 1935, 1963, 1976, and 1986, and a minor eruption in January 2006. We measured the surface displacements of the volcano by radar interferometry and GPS before and after the eruption in 2006. ERS-1/2, RADARSAT-1 and ENVISAT SAR data were used for the study. Multiple interferograms were stacked to reduce artifacts caused by different atmospheric conditions. Least square (LS) method was used to reduce atmospheric artifacts. Singular value decomposition (SVD) method was applied for retrieval of time sequential deformations. Satellite radar interferometry helps to understand the surface displacements system of Augustine volcano. ?? 2007 IEEE.

tourist sea village "Ippocampo". Here, unpublished studies based on ground data indicate average subsidence rates of the order of 0.20 mm/y in the last 125 ka for the inland area next to the village. More recently, height maps issued by the Italian Military Geographic Institute (IGM) in the 1950s report heights a.s.l. of the order of a few m. Observing that today the area is practically at sea level, an average subsidence of the order of tens of mm/y can be inferred for the last 50 years. To gain insight into the recent evolution of these phenomena, we investigate vertical movements on the coastal Tavoliere area through multitemporal differential Interferometric synthetic aperture radar (DInSAR) techniques. We use a persistent scatterers interferometry (PSI) processing methodology [2] to estimate subsidence displacement rates from long temporal series of SAR acquisitions. PSI techniques, first developed at POLIMI [3], allow to retrieve phase information from stacks of co-registered SAR interferograms spanning many years and taken from different directions with large baselines, by restricting the analysis to selected image pixels containing single objects with strong radar backscatter returns. Exploiting the high temporal stability of radar returns from these targets, it is possible to correct the images from spurious phase contributions such as atmospheric phase artefacts and errors in the digital elevation models used to account for topographic InSAR phase. Such stable objects typically coincide with man-made features, so successful applications of PSI techniques are mainly reported over urban centers. We processed a total of 105 SAR images acquired from the ERS-1/2 and ENVISAT satellites, organized in 3 stacks related to both descending (50 ERS-1/2 scenes) and ascending (25 ERS-1/2 and 30 ENVISAT scenes) acquisition geometries. The acquisitions refer to the temporal periods from 1995 to 2000 (ERS) and 2003 to 2008 (ENVISAT), respectively, with a temporal repetition

Geosynchronous Earth Orbit Synthetic Aperture Radar (GEO SAR) runs in the height of 360000Km geosynchronous earth orbit,compared with traditional Low Earth Orbit (LEO) SAR (orbit height under 1000Km),GEO SAR has advantages of shorter repeat period,wider swath and so on.Firstly,the basic principle and state-of-art of GEO SAR in domestic and overseas are introduced.Secondly,coverage characteristic of GEO SAR is analyzed.Thirdly,the key problems of yaw steering and imaging on curved trajectory in GEO SAR are discussed in detail,and the corresponding primary solutions are presented in order to promote future research on GEO SAR.

Full Text Available The paper presents the validation results of the InSAR method for determining the forest canopy height, based on TanDEM-X and ALOS PALSAR data. The research conducted on the territory of the Baikal-Kudara forest area of the Republic of Buryatia (52°10'N, 106°48'E. Forest vegetation is represented mainly by conifers – pine, and spruce, with a small admixture of deciduous trees – aspen, birch, etc. The forest vegetation height was determined by subtracting the digital elevation model (DEM of the digital terrain model (DTM. DEM is built according to the L-band (wavelength of 23.5 cm ALOS PALSAR satellite with horizontal co-polarization mode. In the investigation it was assumed that a radar signal of ALOS PALSAR passes all forest thickness and reflected from the underlying surface, made it possible to recover terrain under forest canopy. DTM has been built using the TanDEM-X data (wavelength 3 cm. In this case, it was assumed that the radar echoes scattered from a some virtual phase centers of scattering surface, which characterizes the upper limit of the continuous forest canopy. To check the accuracy of satellite definitions of forest height in study area were made high-precision geodetic measurement of trees heights using electronic total station and the coordinates of geographic control points using differential GPS receivers. The discrepancy between the satellite and ground-based measurements at 11 test sites did not exceed 2 m, which is mainly due to the difference in measurement techniques: height of individual trees by ground methods and continuous forest canopy height using radar interferometry.

Classical Cepheid stars have been considered since more than a century as reliable tools to estimate distances in the universe thanks to their Period-Luminosity (P-L) relationship. Moreover, they are also powerful astrophysical laboratories, providing fundamental clues for studying the pulsation and evolution of intermediate-mass stars. When in binary systems, we can investigate the age and evolution of the Cepheid, estimate the mass and distance, and constrain theoretical models. However, most of the companions are located too close to the Cepheid (1-40 mas) to be spatially resolved with a 10-meter class telescope. The only way to spatially resolve such systems is to use long-baseline interferometry. Recently, we have started a unique and long-term interferometric program that aims at detecting and characterizing physical parameters of the Cepheid companions, with as main objectives the determination of accurate masses and geometric distances.

Nulling interferometry aims to detect faint objects close to bright stars. Its principle is to produce a destructive interference along the line-of-sight so that the stellar flux is rejected, while the flux of the off-axis source can be transmitted. In practice, various instrumental perturbations can degrade the nulling performance. Any imperfection in phase, amplitude, or polarization produces a spurious flux that leaks to the interferometer output and corrupts the transmitted off-axis flux. One of these instrumental pertubations is the crosstalk phenomenon, which occurs because of multiple parasitic reflections inside transmitting optics, and/or diffraction effects related to beam propagation along finite size optics. It can include a crosstalk of a beam with itself, and a mutual crosstalk between different beams. This can create a parasitic interference pattern, which degrades the intrinsic transmission map - or intensity response - of the interferometer. In this context, we describe how this instrumental ...

The basic sensitivity of moire interferometry was increased beyond the previously conceived theoretical limit. This was accomplished by creating the virtual reference grating inside a refractive medium instead of air, thus shortening the wavelength of light. A very compact four-beam moire interferometer in a refractive medium was developed for microscopic viewing, which produced a basic sensitivity of 208 nm per fringe order, corresponding to moire with 4800 lines per mm. Its configuration made it inherently stable and relatively insensitive to environmental disturbances. An optical microscope was employed as the image recording system to obtain high spatial resolution. The method was demonstrated for deformation of a thick graphite/epoxy composite at the 0/90 deg ply interface.

40 percent of the world's population are presently living in coastal areas or along the main rivers. Taking into account that the vulnerability of these areas is increasing due to sea-level rise and coastal hazards such as storm surges or extreme rainfall events accompanied with floods, the importance of safety structures such as dykes is increasing as well. Hence, a spatial distributed dyke monitoring should be part of a sustainable adaptation strategy. Due to increasing amount of SAR-data from various satellites with high spatial and temporal coverage, the means of SAR-interferometry could be an essential tool to ensure this kind of required monitoring. Given this prospect, Persistent Scattering Interferometry (PSI) will be a very suitable monitoring technique for dyke structures to identify dyke movement with the accuracy of few millimetres. This procedure focuses on pixels that show a stable scattering behaviour in a sequence of multiple SAR-scenes. In opposition to ground-measurements, the spatial coverage of this technique provides comparable results for different parts of the dyke; furthermore weak segments with particular high movements could be identified in advance. This could prevent future dyke crevasses and help to reduce risks in high-populated areas. This paper attempts to describe the potential of the PSI technique for a spatial distributed dyke monitoring at the coast in northern Germany. 21 ERS-2 scenes and 16 Envisat ASAR scenes were analysed. Those Scenes cover an area of a sea shore dyke including a flood regulation barrage and results point out the potential for this technique to monitor dyke structures. Even though the observed dyke doesn't show any significant deformation rates, the two datasets show the same signal for the whole dyke.

Recently Earth Observation by means of active microwave is advancing rapidly. The evolution started from first-generation classical single-channel systems like JERS (JAXA), ERS (ESA) or Radarsat-1 (CSA). With the launch of ALOS-1 (JAXA), the first fully polarimetric SAR measurements became available followed by Radarsat-2 (CSA) and TerraSAR-X (DLR), making polarimetric L-, C-, and X-band data available. In Japanese fiscal year 2013, the third generation of SAR satellites will begin with the launch of ALOS-2. The JAXA cutting-edge follow-on mission to the highly acclaimed ALOS-1 will carry the state-of-the-art PALSAR-2 sensor aboard. Due to its much better orbital revisit cycle of only 14 days and its very high spatial resolution (3 m) the system will be highly suitable for interferometric analysis of polarimetric data obtained from repeat-pass acquisitions. The combination of polarimetry and interferometry is probably the most promising approach for a better estimation of geophysical parameters from SAR data acquired over natural terrain and thus will greatly improve the capabilities to estimate soil moisture under all kinds of vegetation with high accuracy and with high temporal and spatial resolutions. In advent of the 3rd generation of Japanese SAR EO satellites, our group conducts a variety of fundamental research on low-frequency SAR surface scattering/interactions. Here, we present first results from soil moisture experiments based on fully polarimetric GB-SAR (Tohoku University) and Pi-SAR 2L (JAXA) measurements. These experiments comprise investigations of the effective soil moisture measuring depth of L-band SAR. The experimental set-up consists of an array of receiving di-pole antennas installed in different depths to quantify the penetration (and reflection) capabilities of the incoming EM waves. We use a fully polarimetric GB-SAR system based on a high-end VNA capable of coherent measurement of the [S2] scattering matrix. It uses 2 large horn antennas

Full Text Available When synthetic aperture radar interferometry (InSAR technology is applied in the monitoring of land subsidence, the sensor band plays an important role. An X-band SAR system as TerraSAR-X (TSX provides high resolution and short revisit time, but it has no capability of global coverage. On the other side, an L-band sensor as Advanced Land Observing Satellite-Phased Array L-band Synthetic Aperture Radar (ALOS-PALSAR has global coverage and it produces highly coherent interferograms, but it provides much less details in time and space. The characteristics of these two satellites from different bands can be regarded as complementary. In this paper, we firstly present a possible strategy for X-band optimized acquisition planning combining with L-band. More importantly, we also present the multi-temporal InSAR (MT-InSAR analysis results from 23 ALOS-PALSAR images and 37 TSX data, which show the complementarity of L- and X-band allows measuring deformations both in urban and non-urban areas. Furthermore, the validation between MT-INSAR and leveling/GPS has been carried out. The combination analysis of L- and X-band MT-InSAR results effectively avoids the limitation of X-band, providing a way to define the shape and the borderline of subsiding center and helps us to understand the subsidence mechanism. Finally, the geological interpretation of the detected subsidence center is given.

Synthetic Aperture Radar Interferometry (for short, InSAR) is a new kind of earth observation technology, which has obtained great development in recent ten years and has a great development potential and successful future. In this note, three typical regions with different physiognomies and terrains have been selected as study regions to extract their Digital Elevation Model (DEMs). Compared with the existing 1︰250000 DEM and by analyzing their results, we have obtained its accuracy and applicable scopes. The results show that in the region (plains, mountains or highlands) with dry surface and sparse vegetation, because of the better correlatability of images, the DEM obtained by InSAR is evidently better than the existing 1︰250000 DEM and the accuracy can reach 4-6 m; in the thick-vegetation-covering region, correlatability between images descends and the accuracy of InSAR DEM can only reach about 30 m worse than its existing 1︰250000 DEM; in the middle covering field, the accuracy of InSAR DEM with tandem images can reach about 10 m as well; yet in water space, such as lakes and rivers, InSAR DEM shows a big error since there is only quite faint signal reflected to the sensor. Then the conclusion has been got: in the west of China, where it has a lack-vegetation and dry ground, InSAR is completely feasible to be applied to such a complicated nature environment region.

Surface deformation caused by an intrusion and small eruption during June 17-19, 2007, along the East Rift Zone of Kilauea Volcano, Hawaii, was three-dimensionally reconstructed from radar interferograms acquired by the Advanced Land Observing Satellite (ALOS) phased-array type L-band synthetic aperture radar (SAR) (PALSAR) instrument. To retrieve the 3-D surface deformation, a method that combines multiple-aperture interferometry (MAI) and conventional interferometric SAR (InSAR) techniques was applied to one ascending and one descending ALOS PALSAR interferometric pair. The maximum displacements as a result of the intrusion and eruption are about 0.8, 2, and 0.7 m in the east, north, and up components, respectively. The radar-measured 3-D surface deformation agrees with GPS data from 24 sites on the volcano, and the root-mean-square errors in the east, north, and up components of the displacement are 1.6, 3.6, and 2.1 cm, respectively. Since a horizontal deformation of more than 1 m was dominantly in the north-northwest-south-southeast direction, a significant improvement of the north-south component measurement was achieved by the inclusion of MAI measurements that can reach a standard deviation of 3.6 cm. A 3-D deformation reconstruction through the combination of conventional InSAR and MAI will allow for better modeling, and hence, a more comprehensive understanding, of the source geometry associated with volcanic, seismic, and other processes that are manifested by surface deformation.

This paper describes the results from the recently launched SAR satellites for the purpose of subsidence monitoring over underground coal mine sites in the state of New South Wales, Australia, using differential interferometric synthetic aperture radar (DInSAR) technique. The quality of the mine subsidence monitoring results is mainly constrained by noise due to the spatial and temporal decorrelation between the interferometric pair and the phase discontinuities in the interferogram. This paper reports oil the analysis of the impact of these two factors on the performance of DInSAR for monitoring ground deformation. Simulations were carried out prior to real data analyses. SAR data acquired using different operating frequencies, for example, X-, C- and L-band, from the TerraSAR-X, ERS-1/2, ENVISAT, JERS-1 and ALOS satellite missions, were examined. The simulation results showed that the new satellites ALOS, TerraSAR-X and COSMO-SkyMed perform much better than the satellites launched before 2006. ALOS and ENVISAT satellite SAR images with similar temporal coverage were searched for the test site. The ALOS PALSAR DInSAR results have been compared to DInSAR results obtained from ENVISAT ASAR data to investigate the performance of both satellites for ground subsidence monitoring. Strong phase discontinuities and decorrelation have been observed in almost all ENVISAT interferograms and hence it is not possible to generate the displacement maps without errors. However these problems are minimal in ALOS PALSAR interferograms due to its spatial resolution and longer wavelength. Hence ALOS PALSAR is preferred for ground subsidence monitoring in areas covered by vegetation and where there is a high rate ground deformation.

The possibility of the use of an extremely sensitive neutron interferometry technique for the study of electromagnetic structure of the neutron and the parity non-conservative effects in neutron spin rotation is discussed. (author)

Holographic interferometry is well adapted for the determination of 2D strain fields in osseous structures. The knowledge of those strain fields is important for the understanding of structure behavior such as arthrosis.

National Aeronautics and Space Administration — "We are developing rotating-baseline nulling-interferometry techniques and algorithms on the single-aperture Hale and Keck telescopes at near-infrared wavelengths,...

Optical interferometry has empowered an impressive variety of biosensing and medical imaging techniques. A widely held assumption is that devices based on optical interferometry require coherent light to generate a precise optical signature in response to an analyte. Here we disprove that assumption. By directly embedding light emitters into subwavelength cavities of plasmonic interferometers, we demonstrate coherent generation of surface plasmons even when light with extremely low degrees of...

Reference-fringe formation in nondiffuse dual-hologram interferometry is described by combining a first-order geometrical hologram treatment with interference fringes generated by two point sources. The first-order imaging relationships can be used to describe reference-fringe patterns for the geometry of the dual-hologram interferometry. The process can be completed without adjusting the two holograms when the reconstructing wavelength is less than the exposing wavelength, and the process is found to facilitate basic intereferometer adjustments.

Full Text Available Circular Synthetic Aperture Radar (CSAR can acquire targets’ scattering information in all directions by a 360° observation, but a single-track CSAR cannot efficiently obtain height scattering information for a strong directive scatter. In this study, we examine the typical target of the three-dimensional circular SARinterferometry theoryand validate the theory in a darkroom experiment. We present a 3D reconstruction of the actual tank metal model of interferometric CSAR for the first time, verify the validity of the method, and demonstrate the important potential applications of combining 3D reconstruction with omnidirectional observation.

Atmospheric effects are still a limitation to the application of InSAR techniques for displacement measurement. In this study, zenith total delay (ZTD) values derived from global navigation satellite system (GNSS) are used to correct interferograms from tropospheric effects. Displacement measurements are obtained from the corrected interferograms through a persistent scatterer interferometry approach. The influence of different interpolation methods on the construction of ZTD maps is tested through two different algorithms: cubic spline and ordinary kriging. Differences are observed between the cumulative displacement maps obtained with both interpolators, but atmospheric effects are still present, possibly due to the small number of available GNSS stations.

It has been suggested that instability of the western flank of Cumbre Vieja volcano, on the island of La Palma (Canary Islands), could have the potential to result in a lateral collapse of the flank, which in turn could generate an Atlantic tsunami. InSAR measurements provide an excellent way to corroborate data from GPS and structural surveys to provide independent corroboration. This work will use maps of atmospheric phase delay to improve the accuracy of persistent scatterer interferometry results over the island, and integrate these measurements with new GPS data, to give a complete assessment of flank stability and allow better assessment of the risks posed by the volcano.

This paper is focused on the estimation of the thermal expansion of buildings and infrastructures using X-band Persistent Scatterer Interferometry (PSI) observations. For this purpose an extended PSI model is used, which allows separating the thermal expansion from the total observed deformation thus generating a new PSI product: the map of the thermal expansion parameter, named thermal map. The core of the paper is devoted to the exploitation of the information contained in the thermal maps: three examples are discussed in detail, which concern a viaduct, a set of industrial buildings and two skyscrapers. The thermal maps can be used to derive the thermal expansion coefficient of the observed objects and information on their static structure. In addition, the paper illustrates the distortions in the PSI deformation products that occur if the thermal expansion is not explicitly modelled. Finally, an inter-comparison exercise is described, where the thermal expansion coefficients estimated by PSI are compared with those derived by a Ku-band ground-based SAR campaign.

... include: Arterial blood tests Blood clotting tests Blood chemistry tests Chest x-ray or chest CT scan ... The death rate from SARS was 9 to 12% of those diagnosed. In people over age 65, the death ...

The conservation of World Heritage is critical to the cultural and social sustainability of regions and nations. Risk monitoring and preventive diagnosis of threats to heritage sites in any given ecosystem are a complex and challenging task. Taking advantage of the performance of Earth Observation technologies, we measured the impacts of hitherto imperceptible and poorly understood factors of groundwater and temperature variations on the monuments in the Angkor World Heritage site (400 km2). We developed a two-scale synthetic aperture radar interferometry (InSAR) approach. We describe spatial-temporal displacements (at millimeter-level accuracy), as measured by high-resolution TerraSAR/TanDEM-X satellite images, to provide a new solution to resolve the current controversy surrounding the potential structural collapse of monuments in Angkor. Multidisciplinary analysis in conjunction with a deterioration kinetics model offers new insights into the causes that trigger the potential decline of Angkor monuments. Our results show that pumping groundwater for residential and touristic establishments did not threaten the sustainability of monuments during 2011 to 2013; however, seasonal variations of the groundwater table and the thermodynamics of stone materials are factors that could trigger and/or aggravate the deterioration of monuments. These factors amplify known impacts of chemical weathering and biological alteration of temple materials. The InSAR solution reported in this study could have implications for monitoring and sustainable conservation of monuments in World Heritage sites elsewhere. PMID:28275729

Full Text Available A relatively unknown yet powerful technique, the so-called fractional Fourier transform (FrFT, is applied to SAR along-track interferometry (SAR-ATI in order to estimate moving target parameters. By mapping a target's signal onto a fractional Fourier axis, the FrFT permits a constant-velocity target to be focused in the fractional Fourier domain thereby affording orders of magnitude improvement in SCR. Moving target velocity and position parameters are derived and expressed in terms of an optimum fractional angle and a measured fractional Fourier position , allowing a target to be accurately repositioned and its velocity components computed without actually forming an SAR image. The new estimation algorithm is compared with the matched filter bank approach, showing some of the advantages of the FrFT method. The proposed technique is applied to the data acquired by the two-aperture CV580 airborne radar system configured in its along-track mode. Results show that the method is effective in estimating target velocity and position parameters.

Full Text Available The inversion problem concerns the identification of parameters of a volcanic source causing observable changes in ground deformation data recorded in volcanic areas. In particular, this paper deals with the inversion of ground deformation measured by using SAR (Synthetic Aperture Radar interferometry and an inversion approach formulated in terms of an optimization problem is proposed. Based on this inversion scheme, it is shown that the problem of inverting ground deformation data in terms of a single source, of Mogi or Okada type, is numerically well conditioned. In the paper, two case studies of inverting actual SAR data recorded on Mt. Etna during eruptions occurring in 1998 and 2001 are investigated, showing the suitability of the proposed technique.

The problems of simulation of bistatic SAR raw data and focusing are studied. A discrete target simulator is described. The simulator introduces the scene topography and compute the integration time of general bistatic configurations providing a means to derived maps of the range and azimuth spatial resolutions. The problem of focusing of bistatic SAR data acquired in a translational-invariant bistatic configuration is studied by deriving the bistatic Point Target Reference spectrum and presenting an analytical solution for its stationary points.

ERS-1 synthetic aperture radar (SAR) imagery was employed for the measurement of the dynamics of the Bagley icefield during a major surge in 1993-1994, the measurement of ice velocities on the Malaspina piedmont glacier during a quiescent phase between surges, and for mapping the snow lines and the position of the terminus of Nabesna glacier on Mount Wrangell (a 4317 m andesitic shield volcano) in the heavily glacierized Saint Elias and Wrangell Mountains of Alaska. An overview and summary of results is given. The methods used include interferometry, cross-correlation of sequential images, and digitization of boundaries using terrain-corrected SAR imagery.

The urban environment is very complex to interpret on a high resolution radar image, partly because of the presence of many geometric effects due to the radar lateral illumination: the double-bounce scattering, the very strong dynamic between the edges of buildings and horizontal surfaces, the presence of urban canyons, the artefacts due to the imaging process, and so on. It is then very difficult to interpret and distinguish all the effects observed, but also to predict them (for example, see [1]). In this paper, we are particularly interested in understanding the propagation occurring in a urban canyon on PolInSAR data. A urban canyon is an artefact of a urban environment similar to a natural canyon, and can be defined as the free space located between two vertical walls. It is a simple scene to describe but provides a difficult multipath environment to understand. Its interpretation on a PolInSAR image is already sufficiently complex to be the subject of this paper. Our ultimate goal is to determine for which configurations a non line of sight (NLOS) target located within a urban canyon can be detected using multipath, and to find the best method of detection associated. In this context, polarimetry and interferometry are expected to be valuable tools to analyse and differentiate the different electromagnetic returns obtained on a urban canyon. We propose in this paper to use results of simulation and in a first step, we analyse the range profiles, without taking into account the Doppler integration effects. Therefore, for this preliminary study, we have developed a simple simulation tool that does not take into account electromagnetic effects due to diffraction, roughness, and antenna scattering pattern. Using this simple simulation tool,we will try to see if we are able to predict the number of multipath and to determine how sensitive it is to the radar configuration, namely the antenna height. Finally we will study to what extent polarimetric interferometry

State of the art simulations are of great interest when designing a new instrument, studying the imaging mechanisms due to a given scenario or for inversion algorithm design as they allow to analyze and understand the effects of different instrument configurations and targets compositions. In the framework of the studies about a new instruments devoted to the estimation of the ocean surface movements using Synthetic Aperture Radar along-track interferometry (SAR-ATI) an End-to-End simulator has been developed. The simulator, built in a high modular way to allow easy integration of different processing-features, deals with all the basic operations involved in an end to end scenario. This includes the computation of the position and velocity of the platform (airborne/spaceborne) and the geometric parameters defining the SAR scene, the surface definition, the backscattering computation, the atmospheric attenuation, the instrument configuration, and the simulation of the transmission/reception chains and the raw data. In addition, the simulator provides a inSAR processing suit and a sea surface movement retrieval module. Up to four beams (each one composed by a monostatic and a bistatic channel) can be activated. Each channel provides raw data and SLC images with the possibility of choosing between Strip-map and Scansar modes. Moreover, the software offers the possibility of radiometric sensitivity analysis and error analysis due atmospheric disturbances, instrument-noise, interferogram phase-noise, platform velocity and attitude variations. In this paper, the architecture and the capabilities of this simulator will be presented. Meaningful simulation examples will be shown.

In terms of data availability and error correction, landslide forecasting by Differential Interferometric SAR (DInSAR) analysis is not easy task. Especially, the landslides by the anthropogenic construction activities frequently occurred in the localized cutting side of mountainous area. In such circumstances, it is difficult to attain sufficient enough accuracy because of the external factors inducing the error component in electromagnetic wave propagation. For instance, the local climate characteristics such as orographic effect and the proximity to water source can produce the significant anomalies in the water vapor distribution and consequently result in the error components of InSAR phase angle measurements. Moreover the high altitude parts of target area cause the stratified tropospheric delay error in DInSAR measurement. The other obstacle in DInSAR observation over the potential landside site is the vegetation canopy which causes the decorrelation of InSAR phase. Thus rather than C band sensor such as ENVISAT, ERS and RADARSAT, DInSAR analysis with L band ALOS PLASAR is more recommendable. Together with the introduction of L band DInSAR analysis, the improved DInSAR technique to cope all above obstacles is necessary. Thus we employed two approaches i.e. StaMPS/MTI (Stanford Method for Persistent Scatterers/Multi-Temporal InSAR, Hopper et al., 2007) which was newly developed for extracting the reliable deformation values through time series analysis and two pass DInSAR with the error term compensation based on the external weather information in this study. Since the water vapor observation from spaceborne radiometer is not feasible by the temporal gap in this case, the quantities from weather Research Forecasting (WRF) with 1 km spatial resolution was used to address the atmospheric phase error in two pass DInSAR analysis. Also it was observed that base DEM offset with time dependent perpendicular baselines of InSAR time series produce a significant error

Full Text Available Mutation of sarA in Staphylococcus aureus results in a reduced capacity to form a biofilm, but the mechanistic basis for this remains unknown. Previous transcriptional profiling experiments identified a number of genes that are differentially expressed both in a biofilm and in a sarA mutant. This included genes involved in acid tolerance and the production of nucleolytic and proteolytic exoenzymes. Based on this we generated mutations in alsSD, nuc and sspA in the S. aureus clinical isolate UAMS-1 and its isogenic sarA mutant and assessed the impact on biofilm formation. Because expression of alsSD was increased in a biofilm but decreased in a sarA mutant, we also generated a plasmid construct that allowed expression of alsSD in a sarA mutant. Mutation of alsSD limited biofilm formation, but not to the degree observed with the corresponding sarA mutant, and restoration of alsSD expression did not restore the ability to form a biofilm. In contrast, concomitant mutation of sarA and nuc significantly enhanced biofilm formation by comparison to the sarA mutant. Although mutation of sspA had no significant impact on the ability of a sarA mutant to form a biofilm, a combination of protease inhibitors (E-64, 1-10-phenanthroline, and dichloroisocoumarin that was shown to inhibit the production of multiple extracellular proteases without inhibiting growth was also shown to enhance the ability of a sarA mutant to form a biofilm. This effect was evident only when all three inhibitors were used concurrently. This suggests that the reduced capacity of a sarA mutant to form a biofilm involves extracellular proteases of all three classes (serine, cysteine and metalloproteases. Inclusion of protease inhibitors also enhanced biofilm formation in a sarA/nuc mutant, with the combined effect of mutating nuc and adding protease inhibitors resulting in a level of biofilm formation with the sarA mutant that approached that of the UAMS-1 parent strain. These results

Inverting for the subsurface velocity distribution by refraction traveltime tomography is a well-accepted imaging method by both the exploration and earthquake seismology communities. A significant drawback, however, is that the recorded traces become noisier with increasing offset from the source position, and so accurate picking of traveltimes in far-offset traces is often prevented. To enhance the signal-to-noise ratio (SNR) of the far-offset traces, we present the theory of supervirtual refraction interferometry where the SNR of far-offset head-wave arrivals can be theoretically increased by a factor proportional to; here, N is the number of receiver or source positions associated with the recording and generation of the head-wave arrival. There are two steps to this methodology: correlation and summation of the data to generate traces with virtual head-wave arrivals, followed by the convolution of the data with the virtual traces to create traces with supervirtual head-wave arrivals. This method is valid for any medium that generates head-wave arrivals recorded by the geophones. Results with both synthetic traces and field data demonstrate the feasibility of this method. There are at least four significant benefits of supervirtual interferometry: (1) an enhanced SNR of far-offset traces so the first-arrival traveltimes of the noisy far-offset traces can be more reliably picked to extend the useful aperture of the data, (2) the SNR of head waves in a trace that arrive later than the first arrival can be enhanced for accurate traveltime picking and subsequent inversion by later-arrival traveltime tomography, (3) common receiver-pair gathers can be analysed to detect the presence of diving waves in the first arrivals, which can be used to assess the nature of the refracting boundary, and (4) the source statics term is eliminated in the correlation operations so that the timing of the virtual traces is independent of the source excitation time. This suggests the

In the last decade, remote sensing of the temporal variation of ground level and gravity has improved our understanding of groundwater dynamics and storage. Mass changes are measured by GRACE (Gravity Recovery and Climate Experiment) satellites, whereas ground deformation is measured by processing synthetic aperture radar satellites data using the InSAR (Interferometry of Synthetic Aperture Radar) techniques. Both methods are complementary and offer different sensitivities to aquifer system processes. GRACE is sensitive to mass changes over large spatial scales (more than 100,000 km(2) ). As such, it fails in providing groundwater storage change estimates at local or regional scales relevant to most aquifer systems, and at which most groundwater management schemes are applied. However, InSAR measures ground displacement due to aquifer response to fluid-pressure changes. InSAR applications to groundwater depletion assessments are limited to aquifer systems susceptible to measurable deformation. Furthermore, the inversion of InSAR-derived displacement maps into volume of depleted groundwater storage (both reversible and largely irreversible) is confounded by vertical and horizontal variability of sediment compressibility. During the last decade, both techniques have shown increasing interest in the scientific community to complement available in situ observations where they are insufficient. In this review, we present the theoretical and conceptual bases of each method, and present idealized scenarios to highlight the potential benefits and challenges of combining these techniques to remotely assess groundwater storage changes and other aspects of the dynamics of aquifer systems.

Interferometric Synthetic Aperture Radar (SAR) methodology can successfully detect phase variations related to water level changes and produce corresponding water level maps. Two lakes located in Western Crete, Greece, namely Lake Kournas and Lake Agia were used as case studies to study water level change with means of SARinterferometry. The change of the water surface in the lake is examined over a period of two years, 2015-2016 using Sentinel 1 IW mode images and in situ water level data. Initially, all the SAR images were preprocessed in terms of atmospheric and radiometric corrections. Various interferograms were developed to study the multi-temporal regime of water level in both lakes. Optical satellite sensor data (Landsat 8) were used to study the vegetation regime and how this affect the interferogram processing. The results denoted the fact that the combination of SAR backscattering intensity and unwrapped phase water level data can provide additional insight into hydrological state. It is also shown that integrated analysis of the backscattering mechanism and interferometric characteristics can considerably enhance the reliability of the water-level retrieval scheme and optimize the capture of hydrological patterns spatial distribution. Keywords: Sentinel-1, interferogram, water level, Backscattering

In the last decade, remote sensing of the temporal variation of ground level and gravity has improved our understanding of groundwater dynamics and storage. Mass changes are measured by GRACE (Gravity Recovery and Climate Experiment) satellites, whereas ground deformation is measured by processing synthetic aperture radar satellites data using the InSAR (Interferometry of Synthetic Aperture Radar) techniques. Both methods are complementary and offer different sensitivities to aquifer system processes. GRACE is sensitive to mass changes over large spatial scales (more than 100,000 km2). As such, it fails in providing groundwater storage change estimates at local or regional scales relevant to most aquifer systems, and at which most groundwater management schemes are applied. However, InSAR measures ground displacement due to aquifer response to fluid-pressure changes. InSAR applications to groundwater depletion assessments are limited to aquifer systems susceptible to measurable deformation. Furthermore, the inversion of InSAR-derived displacement maps into volume of depleted groundwater storage (both reversible and largely irreversible) is confounded by vertical and horizontal variability of sediment compressibility. During the last decade, both techniques have shown increasing interest in the scientific community to complement available in situ observations where they are insufficient. In this review, we present the theoretical and conceptual bases of each method, and present idealized scenarios to highlight the potential benefits and challenges of combining these techniques to remotely assess groundwater storage changes and other aspects of the dynamics of aquifer systems.

Structural forest biomass estimation from lidar or interferometric SAR (InSAR) has demonstrated better performance than radar-power-based approaches for the higher biomasses (>150 Mg/ha) found in tropical forests. Structural biomass estimation frequently regresses field biomass to some function of forest height. With airborne, 25-m footprint lidar data and fixed-baseline C-band InSAR data over tropical wet forests of La Selva Biological Station, Costa Rica, we compare the use of Fourier transforms of vertical profiles at a few frequencies to the intrinsically low-frequency “average height”. RMS scatters of Fourier-estimated biomass about field-measured biomass improved by 40% and 20% over estimates base on average height from lidar and fixed-baseline InSAR, respectively. Vertical wavelengths between 14 and 100 m were found to best estimate biomass. The same airborne data acquisition over La Selva was used to generate many 10’s of repeat-track L-band InSAR baselines with time delays of 1-72 hours, and vertical wavelengths of 5-100 m. We will estimate biomass from the Fourier transforms of L-band radar power profiles (InSAR complex coherence). The effects of temporal decorrelation will be modeled in the Fourier domain to try to model and reduce their impact. Using L-band polarimetric interferometry, average heights will be estimated as well and biomass regression performance compared to the Fourier transform approach. The more traditional approach of using L-band radar polarimetry will also be compared to structural biomass estimation.

Inhabitants of the Nile Delta in Egypt, especially those who live around the coast, are threatened by two perpetual hazards: (1) sea level rise and encroachment from the Mediterranean Sea and (2) land subsidence that is inherent in deltaic environments. With cities like Alexandria and Port Said currently only one meter above sea level, it is important to understand the nature of the sea level rise and land subsidence, both spatially and temporally, and to be able to quantify these hazards. The magnitude of sea level rise has been actively monitored in stations across the Mediterranean Sea; the subsidence of the Nile Delta, as a whole system however, has not been adequately quantified. We have employed the Differential Synthetic Aperture Radar Interferometry (DInSAR) technique known as Persistent Scatterers Interferometry (PSI) across the entire northern parts of the Nile Delta. A dataset of 106 ENVISAT single look complex (SLC) scenes (four descending tracks: 164, 207, 436, and 479) acquired throughout the time period 2003 to 2010 were obtained from the European Space Agency and utilized for radar interferometric purposes. Multiple combinations of these scenes - used for output optimization and validation - were processed. Due to the nature of the PSI technique, subsidence rates calculated using this technique are values measured from cities and urban areas - where PSI works well. The methodology of choice is to calculate the subsidence rates on a city-by-city basis by: (1) choosing an urban area and cutting the SLC scene stack down to a small area (25 - 200 km2); (2) processing this area multiple times using difference scene and parameter combinations in order to best optimize persistent scatterer (PS) abundance and ground displacement measurements; (3) calibrating the relative ground motion measured by PSI to known locations of minimal subsidence rates. The final result is a spatial representation of the subsidence rates across the Nile Delta in Egypt. Measured

The filamentous bacteria Streptomyces exhibit a complex life cycle involving morphological differentiation and secondary metabolism. A putative membrane protein gene sarA (sco4069), sporulation and antibiotic production related gene A, was partially characterized in Streptomyces coelicolor M145. The gene product had no characterized functional domains and was highly conserved in Streptomyces. Compared with the wild-type M145, the sarA mutant accelerated sporulation and dramatically decreased the production of actinorhodin and undecylprodigiosin.Reverse transcription-polymerase chain reaction analysis showed that SarA influenced antibiotic production by controlling the abundance of actll-orf4 and redZ messenger RNA.

InSAR time series analyses can be fine-tuned for specific applications, yielding a potential increase in benchmark density, precision and reliability. Here we demonstrate the algorithms developed for gas pipeline monitoring, enabling operators to precisely pinpoint unstable locations. This helps asset management in planning, prioritizing and focusing in-situ inspections, thus reducing maintenance costs. In unconsolidated Quaternary soils, ground settlement contributes to possible failure of brittle cast iron gas pipes and their connections to houses. Other risk factors include the age and material of the pipe. The soil dynamics have led to a catastrophic explosion in the city of Amsterdam, which triggered an increased awareness for the significance of this problem. As the extent of the networks can be very wide, InSAR is shown to be a valuable source of information for identifying the hazard regions. We monitor subsidence affecting an urban gas transportation network in the Netherlands using both medium and high resolution SAR data. Results for the 2003-2010 period provide clear insights on the differential subsidence rates in the area. This enables characterization of underground motion that affects the integrity of the pipeline. High resolution SAR data add extra detail of door-to-door pipeline connections, which are vulnerable due to different settlements between house connections and main pipelines. The rates which we measure represent important input in planning of maintenance works. Managers can decide the priority and timing for inspecting the pipelines. The service helps manage the risk and reduce operational cost in gas transportation networks.

Neutron interferometry (NI) is amongst the most precise methods for characterizing neutron interactions by measuring the relative difference between two neutron paths, one of which contains a sample-of-interest. Because neutrons carry magnetic moment and are deeply penetrating, they are excellent probes to investigate properties of magnetic materials. The advantage of NI is its unique sensitivity which allows to directly measure magnetic and structural transitions in materials. Up to now NI has been sparingly used in material research due to its sensitivity to environmental noise. However, recent successes in implementing Quantum Error Correction principles lead to an improved NI design making it robust against mechanical vibrations. Following these advances, a new user facility at the National Institute for Standards and Technology was built to study condensed matter applications, biology and quantum physics. Incorporating cold sample stage inside NI is the first of its kind experiment which can be carried out on large range of temperatures down to 4K. Upon successful realization, it will open new frontiers to characterize magnetic domains, phase transitions and spin properties in a variety of materials such as, for example, iron-based superconductors and spintronic materials. Supported in part by CERC, CIFAR, NSERC and CREATE.

We present parsimonious refraction interferometry and tomography where a densely populated refraction data set can be obtained from two reciprocal and several infill shot gathers. The assumptions are that the refraction arrivals are head waves, and a pair of reciprocal shot gathers and several infill shot gathers are recorded over the line of interest. Refraction traveltimes from these shot gathers are picked and spawned into O(N2) virtual refraction traveltimes generated by N virtual sources, where N is the number of geophones in the 2D survey. The virtual traveltimes can be inverted to give the velocity tomogram. This enormous increase in the number of traveltime picks and associated rays, compared to the many fewer traveltimes from the reciprocal and infill shot gathers, allows for increased model resolution and a better condition number with the system of normal equations. A significant benefit is that the parsimonious survey and the associated traveltime picking is far less time consuming than that for a standard refraction survey with a dense distribution of sources.

The primary objectives of the UAVSAR Project were to: a) develop a miniaturized polarimetric L-band synthetic aperture radar (SAR) for use on an unmanned aerial vehicle (UAV) or piloted vehicle. b) develop the associated processing algorithms for repeat-pass differential interferometric measurements using a single antenna. c) conduct measurements of geophysical interest, particularly changes of rapidly deforming surfaces such as volcanoes or earthquakes. Two complete systems were developed. Operational Science Missions began on February 18, 2009 ... concurrent development and testing of the radar system continues.

National audience; With SARdifferentialinterferometry (DInSAR), the height variation of scatterers can be measured. The accuracy of the measure allows centimeters variation retrieval. We analyse the measure of the height done trought interferometry and the DInSAR measurement. If the variation of height is not take into account in the interferometry measure, the overall height can be surestimated of several hundred of metters. We used DInSAR technique to retrieve the variation of height of t...

Accurate clinical diagnosis of severe acute respiratory syndrome (SARS) based on the current World Health Organization definition is difficult and at times impossible at the early stage of the disease. Both false positive and false negative cases are commonly encountered and this could have far-reaching detrimental effects on the patients, their family and the clinicians alike. Contact history is particularly important in diagnosing SARS in children as their presenting features are often non-specific. The difficulty in making a correct diagnosis is further compounded by the lack of a sensitive rapid diagnostic test. Serology is not particularly helpful in the initial triaging of patients as it takes at least 3 weeks to become positive. Co-infection and other treatable conditions should not be missed and conventional antibiotics should remain as part of the first-line treatment regimen. We report five cases to illustrate the difficulties and dilemmas faced by clinicians in diagnosing SARS in children.

Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

National Aeronautics and Space Administration — In this paper, we propose a novel approach to reduce the noise in Synthetic Aperture Radar (SAR) images using particle filters. Interpretation of SAR images is a...

... Links Clinician Registry Travelers' Health Fact Sheet for SARS Patients and Their Close Contacts Format: Select one ... of the World Health Organization (WHO) . Symptoms of SARS The illness usually begins with a fever (measured ...

National Aeronautics and Space Administration — Neva Ridge Technologies proposes to develop a suite of software tools for the analysis of SAR and InSAR data, focused on having a robust and adopted capability well...

The need for identifying over large areas ongoing instability phenomena and spotting the old ones pushed the boundaries of geotechnical engineering from numerical modeling and point-wise in-situ measurements towards geodesic and geographic sciences. Regardless of the ground-based monitoring techniques' precision and reliability, a larger scale monitoring is often useful to either better correlate the scattered results or to identify additional monitoring points. Using aerial ortho-photogrammetry and site visit recognition represent a good, yet costly method to obtain qualitative information about old inactive landslides. A more suitable approach is using ground-based or satellite radar interferometry (InSAR). The obvious disadvantage of the ground-based system is that the monitoring has to be carried out on a predetermined site while the space-borne system may be set to collect information from various sites in range by each successive passing. The quantitative results acquired through the means of InSAR provide a precise set of information regarding the soil surface displacement, with high accuracy and reliability. They provide a great means of identifying danger zones as well as a way of calibrating and augmenting the classical monitoring techniques. This work describes the possibility of integrating the InSAR measurements with the ground monitoring techniques to identify landslide occurrence hazard and reveal the whole of affected areas even when minute symptoms develop. One of the objectives is to propose InSAR monitoring as a fast and efficient mapping tool to help authorities minimize the damage produced by landslides. It can also provide engineers and scientists additional information to further study landslides dynamics phenomena (such as propagation). Interferometry on SAR data uses phase values from two radar images. When a point changes position, the distance between it and the sensor alters, modifying the phase of the signal. This change is used to

The so-called Lindley paradox is a counterintuitive statistical effect where the Bayesian and frequentist approaches to hypothesis testing give radically different answers, depending on the choice of the prior distribution. In this paper we address the occurrence of the Lindley paradox in optical interferometry and discuss its implications for high-precision measurements. In particular, we focus on phase estimation by Mach–Zehnder interferometers and show how to mitigate the conflict between the two approaches by using suitable priors. - Highlights: • We address the occurence of Lindley paradox in interferometry and discuss its implications for high-precision measurements. • We show how to mitigate the conflict between Bayesian and frequentist approach to interferometry using suitable priors. • Our results apply to calibration of homodyne detectors for quantum tomography.

We are developing a Wide-Field Imaging Interferometry Testbed (WIIT) in support of design studies for NASA's future space interferometry missions, in particular the SPIRIT and SPECS far-infrared/submillimeter interferometers. WIIT operates at optical wavelengths and uses Michelson beam combination to achieve both wide-field imaging and high-resolution spectroscopy. It will be used chiefly to test the feasibility of using a large-format detector array at the image plane of the sky to obtain wide-field interferometry images through mosaicing techniques. In this setup each detector pixel records interferograms corresponding to averaging a particular pointing range on the sky as the optical path length is scanned and as the baseline separation and orientation is varied. The final image is constructed through spatial and spectral Fourier transforms of the recorded interferograms for each pixel, followed by a mosaic/joint-deconvolution procedure of all the pixels. In this manner the image within the pointing range ...

Conventional ground-based astronomical observations suffer from image distortion due to atmospheric turbulence. This can be minimized by choosing suitable geographic locations or adaptive optical techniques, and avoided altogether by using orbital platforms outside the atmosphere. One of the promises of optical intensity interferometry is its independence from atmospherically induced phase fluctuations. By performing narrowband spectral filtering on sunlight and conducting temporal intensity interferometry using actively quenched avalanche photon detectors (APDs), the Solar $g^{(2)}(\\tau)$ signature was directly measured. We observe an averaged photon bunching signal of $g^{(2)}(\\tau) = 1.693 \\pm 0.003$ from the Sun, consistently throughout the day despite fluctuating weather conditions, cloud cover and elevation angle. This demonstrates the robustness of the intensity interferometry technique against atmospheric turbulence and opto-mechanical instabilities, and the feasibility to implement measurement scheme...

Conventional ground-based astronomical observations suffer from image distortion due to atmospheric turbulence. This can be minimized by choosing suitable geographic locations or adaptive optical techniques, and avoided altogether by using orbital platforms outside the atmosphere. One of the promises of optical intensity interferometry is its independence from atmospherically induced phase fluctuations. By performing narrow-band spectral filtering on sunlight and conducting temporal intensity interferometry using actively quenched avalanche photodiodes, the Solar g(2)(τ) signature was directly measured. We observe an averaged photon bunching signal of g(2)(τ) = 1.693 ± 0.003 from the Sun, consistently throughout the day despite fluctuating weather conditions, cloud cover and elevation angle. This demonstrates the robustness of the intensity interferometry technique against atmospheric turbulence and opto-mechanical instabilities, and the feasibility to implement measurement schemes with both large baselines and long integration times.

Full Text Available Interferometry filtering is one of the key steps in obtain high-precision Digital Elevation Model (DEM and Digital Orthophoto Map (DOM. In the case of low-correlation or complicated topography, traditional phase filtering methods fail in balancing noise elimination and phase preservation, which leads to inaccurate interferometric phase. This paper proposed an adaptive iterated nonlocal interferometry filtering method to deal with the problem. Based on the thought of nonlocal filtering, the proposed method filters the image with utilization of the image redundancy information. The smoothing parameter of the method is adaptive to the interferometry, and automatic iteration, in which the window size is adjusted, is applied to improve the filtering precision. Validity of the proposed method is verified by simulated and real data. Comparison with existed methods is given at the same time.

A simple and direct procedure for the rectification of a certain class of airborne SAR data is presented. The relief displacements of SAR data are effectively removed by means of a digital elevation model and the image is transformed to the ground coordinate system. SAR data from the Danish EMISAR...... for the application of SAR data in the difficult process of map revision and updating....

Severe acute respiratory syndrome (SARS) emerged in 2002 as a severe and highly contagious infectious disease that rapidly spread to a number of different countries. The collaborative efforts of the global scientific community have provided, within a short period of time, substantial insights into the molecular biology and immunology of SARS-CoV. Although the outbreak has been contained, there is continuous concern that the virus may resurface into the human population through seasonal changes, animal reservoirs or laboratory accidents. The severe morbidity and mortality associated with SARS make it imperative that an effective vaccine be developed to prevent reemergence and epidemics in the future. Cellular & Molecular Immunology. 2005;2(2):101-105.

Despite much effort and significant progress in recent years, speckle removal for Synthetic Aperture Radar (SAR) image still is a challenging problem in image processing. Unlike the traditional noise filters, which are mainly based on local neighborhood statistical average or frequencies transform, in this paper, we propose a speckle reduction method based on the theory of level set, one form of curvature flow propagation. Firstly, based on partial differential equation, the Lee filter can b...

Recent studies have indicated that for the first time since 1950, intense geophysical activity is occurring at the Santorini volcano. Here, we present and discuss the surface deformation associated with this activity, spanning from January 2011 to February 2012. Analysis of satellite interferometry data was performed using two well-established techniques, namely, Persistent Scatterer Interferometry (PSI) and Small Baseline Subset (SBAS), producing dense line-of-sight (LOS) ground deformation maps. The displacement field was compared with GPS observations from 10 continuous sites installed on Santorini. Results show a clear and large inflation signal, up to 150 mm/yr in the LOS direction, with a radial pattern outward from the center of the caldera. We model the deformation inferred from GPS and InSAR using a Mogi source located north of the Nea Kameni island, at a depth between 3.3 km and 6.3 km and with a volume change rate in the range of 12 million m3 to 24 million m3 per year. The latest InSAR and GPS data suggest that the intense geophysical activity has started to diminish since the end of February 2012.

Segmentation of Synthetic Aperture Radar (SAR) images has several uses, but it is a difficult task due to a number of properties related to SAR images. In this article we show how Convolutional Neural Networks (CNNs) can easily be trained for SAR image segmentation with good results. Besides...

Synthetic Aperture Radar (SAR) is today a valuable source of remote sensing information. SAR is a side-looking imaging radar and operates from airborne and spacebome platforms. Coverage, resolution and image quality are strongly influenced by the platform. SAR processing can be performed on standard

Synthetic Aperture Radar (SAR) is today a valuable source of remote sensing information. SAR is a side-looking imaging radar and operates from airborne and spacebome platforms. Coverage, resolution and image quality are strongly influenced by the platform. SAR processing can be performed on standard

Theoretical analysis of polarization filtering of synthetic-aperture-radar (SAR) returns provide hybrid method applied to either (1) maximize signal-to-noise ratio of return from given target or (2) enhance contrast between targets of two different types (that have different polarization properties). Method valid for both point and extended targets and for both monostatic and bistatic radars as well as SAR. Polarization information in return signals provides more complete description of radar-scattering properties of targets and used to obtain additional information about targets for use in classifying them, discriminating between them, or enhancing features of radar images.

We analyze the temporal characteristics of the creeping section of the San Andreas fault in Central California, using persistent scatterer interferometry (PS-InSAR) time series methods. In PS-InSAR, we identify a network of pixels whose scattering properties vary little between multiple SAR acquisitions spanning a period of time and use phase measurements at these points as a function of time to derive deformations. Applying PS-InSAR to natural terrains where conventional interferograms tend to suffer decorrelation is difficult, yet several PS-InSAR methods have been proposed and have been shown to work reliably in urban environments. The Stanford Method for PS (StaMPS) was the first method developed to extend the scope of PS-InSAR to work effectively in vegetated regions. We applied a maximum likelihood approach to PS selection and find it to be effective in identifying PS points in vegetated areas of the San Francisco Bay Area and Imperial Valley in California, USA. A key advantage of both StaMPS and the maximum likelihood method are that they do not require an a priori temporal model for the deformation pattern. Here we present results from applying these methods to the creeping section of the San Andreas fault. This segment of the fault creeps at rates in excess of 20 mm per year. Geodetic measurements in this area from creepmeters, alignment arrays and GPS typically have poor spatial and/or temporal resolution. Conventional stacking of ERS interferograms covering this segment of the fault provides good surface deformation information in parts of this region, but is not viable in areas that are heavily decorrelated due to vegetation and topography. The PS methods generate time series of surface displacement, even in steep, vegetated areas, and readily reproduce the creep rate of about 26 mm/yr along the fault and the spatial distribution of deformation away from the fault. The results are consistent, but more detailed than, the observations from GPS networks

Monitoring represents the main tool for carrying out evaluation procedures and criteria for spatial and temporal landslide forecast. The forecast of landslide behaviour depends on the possibility to identify either evidences of activity (displacement, velocity, volume of unstable mass, direction of displacement, and their temporal variation) or triggering parameters (rainfalls). Generally, traditional geotechnical landslide monitoring technologies permit to define, if correctly positioned and with adequate accuracy, the critical value of displacement and/or acceleration into landslide body. In most cases, they do not allow real time warning signs to be generated, due to environmental induced errors, and the information is related to few points on unstable area. Remote-sensing monitoring instruments are capable of inspecting an unstable slope with high spatial and temporal frequency, but allow solely measurements of superficial displacements and deformations. Among these latest technologies, the satellite Persistent Scatterer SARInterferometry (PSInSAR) is very useful to investigate the unstable area both in terms of space and time. Indeed, this technique allows to analyse wide areas, individuate critical unstable areas, not identifiable by means detailed in situ surveys, and study the phenomenon evolution in a long time-scale. Although this technique usually adopts, as first approximation, a linear model to describe the displacement of the detected targets, also non-linear models can be used. However, the satellite revisit time, which defines the time sampling of the detected displacement signal, limits the maximum measurable velocity and acceleration. This makes it difficult to assess in the short time any acceleration indicating a loss of equilibrium and, therefore, a probable reactivation of the landslide. The recent Sentinel-1 mission from the European Space Agency (ESA), provides a spatial resolution comparable to the previous ESA missions, but a nominal

Severe acute respiratory syndrome (SARS) is characterized by acute respiratory distress syndrome (ARDS) and pulmonary fibrosis, and monocytes/macrophages are the key players in the pathogenesis of SARS. In this study, we compared the transcriptional profiles of SARS coronavirus (SARS-CoV)-infected monocytic cells against that infected by coronavirus 229E (CoV-229E). Total RNA was extracted from infected DC-SIGN-transfected monocytes (THP-1-DC-SIGN) at 6 and 24 h after infection, and the gene expression was profiled in oligonucleotide-based microarrays. Analysis of immune-related gene expression profiles showed that at 24 h after SARS-CoV infection: (1) IFN-α/β-inducible and cathepsin/proteasome genes were downregulated; (2) hypoxia/hyperoxia-related genes were upregulated; and (3) TLR/TLR-signaling, cytokine/cytokine receptor-related, chemokine/chemokine receptor-related, lysosome-related, MHC/chaperon-related, and fibrosis-related genes were differentially regulated. These results elucidate that SARS-CoV infection regulates immune-related genes in monocytes/macrophages, which may be important to the pathogenesis of SARS.

Differential interferometric synthetic aperture radar (SAR) (DInSAR) has proven to be very useful in mapping and monitoring land subsidence in many regions of the world. Shanghai, China's largest city, is one of such areas suffering from land subsidence as a result of severe withdrawal of groundwater for different usages. DInSAR application in Shanghai with the C-band European Remote Sensing 1 & 2 (ERS-1/2) SAR data has been difficult mainly due to the problem of decorrelation of InSAR pairs with temporal baselines larger than 10 months. To overcome the coherence loss of C-band InSAR data, we used eight L-band Japanese Earth Resource Satellite (JERS-1) SAR data acquired during 2 October 1992 to 15 July 1998 to study land subsidence phenomenon in Shanghai. Three of the images were used to produce two separate digital elevation models (DEMs) of the study area to remove topographic fringes from the interferograms used for subsidence mapping. Six interferograms were used to generate 2 different time series of deformation maps over Shanghai. The cumulative subsidence map generated from each of the time series is in agreement with the land subsidence measurements of Shanghai city from 1990-1998, produced from other survey methods. ?? 2007 IEEE.

Taking an innovative look at Synthetic Aperture Radar (SAR), this practical reference fully covers new developments in SAR and its various methodologies and enables readers to interpret SAR imagery An essential reference on polarimetric Synthetic Aperture Radar (SAR), this book uses scattering theory and radiative transfer theory as a basis for its treatment of topics. It is organized to include theoretical scattering models and SAR data analysis techniques, and presents cutting-edge research on theoretical modelling of terrain surface. The book includes quantitative app

In order to demonstrate the capabilities of white-light interferometry depth profiling (WLI-DP) for ancient coinage assessment, we investigated a series of notorious 1786 gold coins, bearing Louis XVI's `horned' effigy, and allegedly minted in Strasbourg. Scanning electron microscopy as well as WLI-DP observations unambiguously indicate that both previously differentiated `single'- and `double'-horned varieties originated from a unique minting tool. Moreover, from topological measurements, we infer that `single-horned' coins, rather than wearing out into `double-horned' coins, proceeded from the latter variety during minting by progressive failure of an already altered die. Whereas present observations do not exclude initial forgery, they suggest that protrusions resulted from progressive incidental in-service die deterioration.

The monochromatic and polychromatic performance of a grating interferometer is theoretically analysed. The smallest detectable refraction angle is used as a metric for the efficiency in acquiring a differential phase-contrast image. Analytical formulae for the visibility and the smallest detectable refraction angle are derived for Talbot-type and Talbot-Lau-type interferometers, respectively, providing a framework for the optimization of the geometry. The polychromatic performance of a grating interferometer is investigated analytically by calculating the energy-dependent interference fringe visibility, the spectral acceptance and the polychromatic interference fringe visibility. The optimization of grating interferometry is a crucial step for the design of application-specific systems with maximum performance.

The combination of frequency-modulated continuous-wave (FMCW) technology and synthetic aperture radar (SAR) techniques leads to lightweight cost-effective imaging sensors of high resolution. One limiting factor to the use of FMCW sensors is the well-known presence of nonlinearities in the

Interferometric Synthetic Aperture Radar (InSAR) is investigated as a method for 3D tree mapping. When operational, the method may be important for monitoring forests with a persistent cloud cover such as tropical rain forests. The problem of crown displacement due to lay-over in a vegetation with a

In this podcast for kids, the Kidtastics talk about the SARS outbreak and how CDC worked to solve the mystery. Created: 5/22/2014 by National Center for Immunization and Respiratory Diseases (NCIRD). Date Released: 5/22/2014.

A light weight SAR has been designed, suitable for short range tactical UAVs, consisting of a fully digital receive array, and a very compact active transmit antenna. The weight of the complete RF front is expected to be below 3 kg, with a power consumption below 30 W. This X-band system can provide

Severe acute respiratory syndrome (SARS) and avian influenza are two important newly emerged infections with pandemic potential. Both infections have crossed the species barrier to infect humans. SARS originated from southern China and spread to many countries in early 2003. The close collaboration of scientists around the world resulted in a rapid identification of the causative agent, and the early isolation of infected cases and meticulous infection control measures were the key to successfully controlling the outbreak of SARS. The first outbreak of human cases of avian influenza was reported in 1997 in Hong Kong. Since 2003, there have been many small outbreaks of human cases around the world, and the reported mortality is greater than 50%. Current evidence suggests that the human-to-human transmission of avian influenza is rather inefficient, but mutation might occur in the future resulting in improved transmission and possibly a pandemic in humans. As with the outbreak of SARS, the development of sensitive and accurate early diagnostic tests is extremely important for successful control of the outbreak at source. The availability of isolation facilities, the stockpiling of antiviral agents and effective and safe vaccination will be extremely important in minimising the damage of a new influenza pandemic.

Full Text Available Previous decade has seen an achievement of large interferometricprojects including 8-10m telescopes and 100m class baselines. Modern computerand control technology has enabled the interferometric combination of lightfrom separate telescopes also in the visible and infrared regimes. Imagingwith milli-arcsecond (mas resolution and astrometry with micro-arcsecond($mu$as precision have thus become reality. Here, I review the methods andinstrumentation corresponding to the current state in the field ofastronomical optical interferometry. First, this review summarizes thedevelopment from the pioneering works of Fizeau and Michelson. Next, thefundamental observables are described, followed by the discussion of the basicdesign principles of modern interferometers. The basic interferometrictechniques such as speckle and aperture masking interferometry, aperture synthesisand nulling interferometry are disscused as well. Using the experience ofpast and existing facilities to illustrate important points, I considerparticularly the new generation of large interferometers that has beenrecently commissioned (most notably, the CHARA, Keck, VLT and LBTInterferometers. Finally, I discuss the longer-term future of opticalinterferometry, including the possibilities of new large-scale ground-based projects and prospects for space interferometry.

In light of presently considered lunar missions, we investigate the feasibility of the basic radio interferometry (RIF) for lunar missions. We discuss the deployment of two-element radio interferometer on the Moon surface. With the first antenna element is envisaged to be placed on the lunar lander,

We apply the new constraints from atom-interferometry searches for screening mechanisms to the symmetron model, finding that these experiments exclude a previously unexplored region of parameter space. We discuss the possibility of networks of domain walls forming in the vacuum chamber, and how this could be used to discriminate between models of screening.

Computerized ionospheric tomography (CIT) based on spaceborne synthetic aperture radar (SAR) is an emerging technique to construct the three-dimensional (3-D) image of ionosphere. The current studies are all based on the Low Earth Orbit synthetic aperture radar (LEO SAR) which is limited by long repeat period and small coverage. In this paper, a novel ionospheric 3-D CIT technique based on geosynchronous SAR (GEO SAR) is put forward. First, several influences of complex atmospheric environment on GEO SAR focusing are detailedly analyzed, including background ionosphere and multiple scattering effects (induced by turbulent ionosphere), tropospheric effects, and random noises. Then the corresponding GEO SAR signal model is constructed with consideration of the temporal-variant background ionosphere within the GEO SAR long integration time (typically 100 s to 1000 s level). Concurrently, an accurate total electron content (TEC) retrieval method based on GEO SAR data is put forward through subband division in range and subaperture division in azimuth, obtaining variant TEC value with respect to the azimuth time. The processing steps of GEO SAR CIT are given and discussed. Owing to the short repeat period and large coverage area, GEO SAR CIT has potentials of covering the specific space continuously and completely and resultantly has excellent real-time performance. Finally, the TEC retrieval and GEO SAR CIT construction are performed by employing a numerical study based on the meteorological data. The feasibility and correctness of the proposed methods are verified.

SARS is a new kind of pneumonia. From the end of 2002 to the beginning of 2003, SARS broke in Guangdong province, Hong Kong and Beijing, and then gradually spread to the world. SARS is extremely contagious. The symptoms of SARS progress very quickly. SARS smashes the people's tranquil life and many people live in horror, worry and anxiety. But if we review the medical history of pneumonia, we would have a better understanding of SARS. This article focuses the history of people's understanding of pneumonia on the historical documents, diagnosis, etiology and treatment. Through the epidemic of SARS, the author hopes to express that contagion will live with us for a long time, but it is not a deadly disease. It is preventable and good care is essential for contagious patients. As Chinese people, we should have the best use of TCM in our combat with contagion.

Augustine Island is a small, 8x11 km island in South Central Alaska's lower Cook Inlet. It is approximately 280 km southwest of Anchorage, and occupied entirely by its namesake Augustine Volcano. At Augustine Volcano, SAR data suitable for interferometry is available from 1992 to 2005, from March 2006 to April 2007, and from July 2007 to October 2010. Its last two eruptive episodes, in 1986 and 2006, resulted in substantial pyroclastic flow deposits (PFDs) on the Volcano's north flank. Earlier InSAR analyses of the area, from 1992-1999, identified local subsidence, but no volcano-wide deformation indicative of magma-chamber evacuation. In contrast to previous studies, we use InSAR data to determine a range of geophysical parameters for PFDs emplaced during the Augustine's two most recent eruption cycles. Based on InSAR measurements between 1992 and 2010, we reconstruct the deformation behavior of PFDs emplaced during Augustine's last two eruption cycles. Using a combination of InSAR measurements and modeling, we determine the thickness and long-term deformation of overlaying pyroclastic flow deposits emplaced in 1986 and 2006. Consistent with previous observations of pyroclastic flows, we found that the PFDs on Augustine Island rapidly subsided after emplacement due to an initial compaction of the material. We determined the length of this initial settling period and measured the compaction rate. Subsequent to this initial rapid subsidence, we found that PFD deformation slowed to a more persistent, linear, long-term rate, related to cooling of the deposits. We established that the deposits' contraction rate is linearly related to their thickness and measured the contraction rate. Finally, a study of long term coherence properties of the Augustine PFDs showed remarkable stability of the surface over long time periods. This information provides clues on the structural properties and composition of the emplaced material.

Advanced remote sensing techniques based on space-borne Synthetic Aperture Radar (SAR) have been developed during the last decade showing their applicability for the monitoring of surface displacements in landslide areas. This paper presents an advanced Persistent Scatterer Interferometry (PSI) processing based on the Stable Point Network (SPN) technique, developed by the company Altamira-Information, for the monitoring of an active slowmoving landslide in the mountainous environment of El Portalet, Central Spanish Pyrenees. For this purpose, two TerraSAR-X data sets acquired in ascending mode corresponding to the period from April to November 2011, and from August to November 2013, respectively, are employed. The objective of this work is twofold. On the one hand, the benefits of employing Nonlocal Interferomtric SAR (NL-InSAR) adaptive filtering techniques over vegetated scenarios to maximize the chances of detecting natural distributed scatterers, such as bare or rocky areas, and deterministic point-like scatterers, such as man-made structures or poles, is put forward. In this context, the final PSI displacement maps retrieved with the proposed filtering technique are compared in terms of pixels' density and quality with classical PSI, showing a significant improvement. On the other hand, since SAR systems are only sensitive to detect displacements in the line-of-sight (LOS) direction, the importance of projecting the PSI displacement results retrieved along the steepest gradient of the terrain slope is discussed. The improvements presented in this paper are particularly interesting in these type of applications since they clearly allow to better determine the extension and dynamics of complex landslide phenomena.

Full Text Available Sinkholes are an unpredictable geohazard that endanger life and property in dolomitic terrains. Sinkholes are a significant threat in Gauteng, South Africa’s most populated and urbanized province. Small-scale surface subsidence is frequently present...

The Shiguanhe river basin is subjected to strong human pressure; it faces severe water management problems, concerning flooding and irrigation in particular. This basin is a complex hydraulic system, including many dams and irrigation channels. Here, an attempt at developing a complete water resources assessment is proposed. The tools for this assessment are described: they concern both hydrological modelling and remote sensing. A specific methodology has been adopted to represent the irrigation, in a three-step approach. Firstly the irrigation outside the basin, secondly the irrigation inside the basin, and lastly the rice farming techniques impacts on the basin's hydrological behaviour are taken into account. Finally, we obtained a good representation of the major hydrological processes taking place in such a complex human-modified system.

The phase estimation of cross-track multibaseline synthetic aperture interferometric data is usually thought to be very efficiently achieved using the maximum likelihood (ML) method. The suitability of this method is investigated here as applied to airborne single pass multibaseline data. Experimental interferometric data acquired with a Ka-band sensor were processed using (a) a ML method that fuses the complex data from all receivers and (b) a coarse-to-fine method that only uses the intermediate baselines to unwrap the phase values from the longest baseline. The phase noise was analyzed for both methods: in most cases, a small improvement was found when the ML method was used.

The phase estimation of cross-track multibaseline synthetic aperture interferometric data is usually thought to be very efficiently achieved using the maximum likelihood (ML) method. The suitability of this method is investigated here as applied to airborne single pass multibaseline data. Experimental interferometric data acquired with a Ka-band sensor were processed using (a) a ML method that fuses the complex data from all receivers and (b) a coarse-to-fine method that only uses the interme...

This paper proposes the design of a 6-bit single-ended SAR ADC with a variable sampling rate at a maximum achievable speed of 50 MS/s. The SAR ADC utilizes the split capacitor array DAC with a non-conventional split-capacitor value. The influence of switches in the capacitive DAC on the ADC's non-linearity is analysed. According to the fulfilled analysis the recommendations for switches and capacitor array dimensioning are given to provide a minimum differential non-linearity (DNL). At a sampling rate of 50 MS/s, the SAR ADC achieves an ENOB of 5.4 bit at an input signal frequency of 1 MHz and consumes 1.2 mW at a 1.8 V power supply, resulting in an energy efficiency of 568 fJ/conv.-step. The SAR ADC was simulated with parasitics in a standard 180nm CMOS process.

Full Text Available The effects of ground deformation pose a significant geo-hazard to the environment and infrastructure in Wuhan, the most populous city in Central China, in the eastern Jianghan Plain at the intersection of the Yangtze and Han rivers. Prior to this study, however, rates and patterns of region-wide ground deformation in Wuhan were little known. Here we employ multi-temporal SARinterferometry to detect and characterize spatiotemporal variations of ground deformation in major metropolitan areas in Wuhan. A total of twelve TerraSAR-X images acquired during 2009–2010 are used in the InSAR time series analysis. InSAR-derived results are validated by levelling survey measurements and reveal a distinct subsidence pattern within six zones in major commercial and industrial areas, with a maximum subsidence rate up to −67.3 mm/year. A comparison analysis between subsiding patterns and urban developments as well as geological conditions suggests that land subsidence in Wuhan is mainly attributed to anthropogenic activities, natural compaction of soft soil, and karst dissolution of subsurface carbonate rocks. However, anthropogenic activities related to intensive municipal construction and industrial production have more significant impacts on the measured subsidence than natural factors. Moreover, remarkable signals of secular land uplift are found along both banks of the Yangtze River, especially along the southern bank, with deformation rates ranging mostly from +5 mm/year to +17.5 mm/year. A strong temporal correlation is highlighted between the detected displacement evolutions and the water level records of the Yangtze River, inferring that this previously unknown deformation phenomenon is likely related to seasonal fluctuations in water levels of the Yangtze River.

针对在地形复杂的矿区沉降观测资料不易获取的问题,将合成孔径雷达差分干涉技术( D-InSAR)与灰色Verhulst模型相结合,提出了一种矿山开采沉陷监测和预计方法。该方法首先对覆盖大柳塔煤矿某工作面的12景TerraSAR-X雷达数据进行D-InSAR处理,获取观测站沉降值；然后根据沉降量与时间的关系建立了基于灰色Ver-hulst模型的预测函数,对开采沉陷发展规律进行分析。试验结果表明：3个测试点D-InSAR监测数据的绝对和相对误差分别为2.8~15 mm,0.9%~6%；结合灰色Verhulst模型预测的绝对和相对误差分别为3.4~18.8 mm,1.2%~5.7%。上述研究结果进一步表明,所提出的方法可有效弥补矿区沉降实测数据的不足,为实现矿区开采沉陷监测和预计的一体化软件设计提供参考。%It is not easy to obtain the observation data of mining subsidence of the mining area with complex terrain. In order to solve the problem,a new mining subsidence monitoring and prediction method based on the combination of synthetic aperture radar differentialinterferometry( D-InSAR) technique and grey Verhulst model is proposed. Firstly,the 12 Terra SAR-X images that covered the experimental areas in the one working face of Daliuta coal mine are processed by using D-InSAR technique to obtain the subsidence values of observation stations. Secondly,the prediction function of grey Verhulst model is es-tablished based on the relationship of subsidence value and time to analyze the development law of mining subsidence. The ex-perimental results show that,the absolute and the relative errors of D-InSAR monitoring values for three points are varied from 2. 8 to 15 mm,and 0. 9% to 6% respectively;The absolute error and relative error in prediction based on the grey Verhulst model Combined with D-InSAR technique are varied from 3. 4 to 18. 8 mm,and from 1. 2% to 5. 7% respectively. The experi-mental results above further indicate that, the

We present a computing framework for studying the spatio-temporal evolution of ground deformation from interferometric synthetic aperture radar (InSAR) data. Several open-source tools including Repeat Orbit Interferometry PACkage (ROI-PAC) and InSAR Scientific Computing Environment (ISCE) from NASA-JPL, and Delft Object-oriented Repeat Interferometric Software (DORIS), have enabled scientists to generate individual interferograms from raw radar data with relative ease. Numerous computational techniques and algorithms that reduce phase information from multiple interferograms to a deformation time-series have been developed and verified over the past decade. However, the sharing and direct comparison of products from multiple processing approaches has been hindered by - 1) absence of simple standards for sharing of estimated time-series products, 2) use of proprietary software tools with license restrictions and 3) the closed source nature of the exact implementation of many of these algorithms. We have developed this computing framework to address all of the above issues. We attempt to take the first steps towards creating a community software repository for InSAR time-series analysis. To date, we have implemented the short baseline subset algorithm (SBAS), NSBAS and multi-scale interferometric time-series (MInTS) in this framework and the associated source code is included in the GIAnT distribution. A number of the associated routines have been optimized for performance and scalability with large data sets. Some of the new features in our processing framework are - 1) the use of daily solutions from continuous GPS stations to correct for orbit errors, 2) the use of meteorological data sets to estimate the tropospheric delay screen and 3) a data-driven bootstrapping approach to estimate the uncertainties associated with estimated time-series products. We are currently working on incorporating tidal load corrections for individual interferograms and propagation of

In synthetic-aperture radar (SAR) returned signals, ground-target vibrations introduce a phase modulation that is linearly proportional to the vibration displacement. Such modulation, termed the micro-Doppler effect, introduces ghost targets along the azimuth direction in reconstructed SAR images that prevents SAR from forming focused images of the vibrating targets. Recently, a discrete fractional Fourier transform (DFrFT) based method was developed to estimate the vibration frequencies and instantaneous vibration accelerations of the vibrating targets from SAR returned signals. In this paper, a demodulation-based algorithm is proposed to reconstruct focused SAR images of vibrating targets by exploiting the estimation results of the DFrFT-based vibration estimation method. For a single-component harmonic vibration, the history of the vibration displacement is first estimated from the estimated vibration frequency and the instantaneous vibration accelerations. Then a reference signal whose phase is modulated by the estimated vibration displacement with a delay of 180 degree is constructed. After that, the SAR phase history from the vibration target is multiplied by the reference signal and the vibration-induced phase modulation is canceled. Finally, the SAR image containing the re-focused vibration target is obtained by applying the 2-D Fourier transform to the demodulated SAR phase history. This algorithm is applied to simulated SAR data and successfully reconstructs the SAR image containing the re-focused vibrating target.

The capture, containment and long-term storage of CO2 is increasingly discussed as an important means to counter climate change resulting from the ongoing release of greenhouse gases into the atmosphere. This CO2 sequestration often requires the pumping of the gas into deep saline aquifers. However, before sequestration can be regarded as a longterm solution it is necessary to investigate under which conditions permanent and leakless capture of the CO2 is achieved in the substrate. We demonstrate that a combination of spaceborne synthetic aperture interferometry (InSAR) and ground based measurements of ground uplift caused by the underground release and spreading of the CO2 can be forged into a powerful tool to monitor sequsetration. We use a novel InSAR approach, which combines the benefits of a point-based persistent scatterer algorithm with a network inversion approach, and an additional temporal filter to remove atmospheric disturbances also at smaller scales down to 1 km and less. Using case studies from several injection wells we show that InSAR and ground based data in conjunction with geological and structural information above the aquifer, as well as detailed injection logs, allow to monitor the volumetric spread of CO2 at the mm per year level. For the majority of the studied wells CO2 appears to approach a stable sequestration state, however, in at least one case our results suggest leakage outside the aquifer.

Interferometry Synthetic Aperture Radar (InSAR)can only measure one component of the surface deformation in the satellite's line of sight (LOS) instead of that in vertical and horizontal directions, i.e. LOS Amphibious. In view of this problem, we analyzed and summarized some methods that can measure the three-dimensional deformation of ground surface by using D-InSAR, developed the calculation model of measuring the three-dimensional co-seismic deformation filed by using the ascending and descending orbit SAR data. The Formula of left-looking (both ascending and descending orbit data), right-looking (both ascending and descending orbit data) and general expression were proposed. The model was applied on L'Aquila earthquake, and the results reveal that the earthquake has caused displacement in both vertical and horizontal directions, and the earthquake made the area down lift 16.8cm along the vertical direction. The characters of the surface reflected by the results are very consistent with the geological exploration.

A desired rotation of a synthetic aperture radar (SAR) image can be facilitated by adjusting a SAR data collection operation based on the desired rotation. The SAR data collected by the adjusted SAR data collection operation can be efficiently exploited to form therefrom a SAR image having the desired rotational orientation.

Volcanic processes which produce a variety of geological and hydrological hazards are difficult to predict and capable of triggering natural disasters on regional to global scales. Therefore it is important to monitor volcano continuously and with a high spatial and temporal sampling rate. The monitoring of active volcanoes requires the reliable measurement of surface deformation before, during and after volcanic activities and it helps for the better understanding and modelling of the involved geophysical processes. Space-borne synthetic aperture radar (SAR) interferometry (InSAR), persistent scatterer interferometry (PSI) and small baseline subset algorithm (SBAS) provide a powerful tool for observing the eruptive activities and measuring the surface changes of millimetre accuracy. All the mentioned techniques with deformation time series extraction address the challenges by exploiting medium to large SAR image stacks. The process of selecting, ordering, downloading, storing, logging, extracting and preparing the data for processing is very time consuming has to be done manually for every single data-stack. In many cases it is even an iterative process which has to be done regularly and continuously. Therefore, data processing becomes slow which causes significant delays in data delivery. The SAR Satellite based High Resolution Data Acquisition System, which will be developed at DLR, will automate this entire time consuming tasks and allows an operational volcano monitoring system. Every 24 hours the system runs for searching new acquired scene over the volcanoes and keeps track of the data orders, log the status and download the provided data via ftp-transfer including E-Mail alert. Furthermore, the system will deliver specified reports and maps to a database for review and use by specialists. The user interaction will be minimized and iterative processes will be totally avoided. In this presentation, a prototype of SAR Satellite based High Resolution Data

The Mackenzie Delta is a unique region in the Canadian North which is rich in hydrocarbons and supports a fragile ecosystem. A need exists to define nominal remote coastal conditions prior to hydrocarbon extraction and to assist in monitoring conditions once t